Egocentric multimodal assistants see through the user's eyes and guide what the user does next, so their outputs directly shape physical actions, including those that affect bystanders. Yet existing safety evaluations do not distinguish whom a response would harm, and score only whether a model refuses. Pooling all harms into one refusal rate hides two failures: a model may protect one target but not another, and it may refuse without understanding the risk, or understand it and comply anyway. We present STOU, a benchmark of 2,902 egocentric video-audio and video-text queries whose potential harm targets the user (Self), co-present individuals (The Others), or society at large (Others). Our evaluation decouples safety understanding from refusal behavior: beyond refusal, we score whether the model recognizes the user's intent, the presence and target of harm, and its downstream consequences. Across 10 open and closed source omnimodal and multimodal LLMs, we find that refusal varies systematically with the harm target, and that models often recognize a harm yet still assist with it. These results show that refusal rates alone cannot certify an assistant as safe, and that safety alignment must account for who would be harmed. Project page: https://onedayoneyeah.github.io/safety-for-whom
Figures & tables
Figure 1: Safety-critical scenarios for egocentric multimodal assistants. The model takes an egocentric video and audio query from the user as input, and responds in text or audio. We introduce four harm targets — Self , The Others , Others , and Unspecified —based on whether the target is identifiable or visible in the video and who may be harmed. We evaluate how well models defend against harmful queries and understand their potential harm across these targets.
Benchmark
View
Modality
Query
Evaluation
Domain
Video
Size
Length
V
A
T
Target
Understanding
Video-SafetyBench
Exo
Adversarial
General
Synthetic
2.3k
10 s
Omni-SafetyBench
Exo
Adversarial
General
Synthetic
23.3k
—
iSafetyBench
Exo
Diagnostic QA
Industrial
Real
1.1k
4–8 s
EgoSafetyBench
Ego
–
Home / Factory
Rendered
1.2k
5 s
EgoSafe-Bench
Ego
Diagnostic QA
Security
Real
12k
∼ 10 s
Table 1: Comparison with existing video safety benchmarks. STOU uniquely evaluates egocentric multimodal assistants with egocentric video and harmful user queries in audio, while incorporating potential harm targets in real-world interactions as a critical evaluation axis for comprehensive safety assessment. Beyond refusal behavior, STOU evaluates assistants’ understanding of query harmfulness. V, A, and T denote video, audio, and text input modalities, respectively.
Figure 2: Composition of STOU by harm target and harm type . By combining two harm dimensions, STOU comprises 2,902 samples spanning four harm targets (left) and six harm types (right), representing diverse real-world scenarios.
Figure 3: Harm-directed harmful text query generation pipeline. We first sample a scenario by harm target and harm type, and pair it with a video description. We then set a target phrase for the chosen harm target. For example, when the target is The Others , a visible person is taken from the video description as the target phrase; if no other person appears, another video is used. The scenario, video description, and target phrase are given to an LLM to generate a harmful text query. For human-written queries, annotators view the video and write the query using the same logic.
Figure 4: Safety understanding evaluation framework. Given a harmful query, the model identifies the user’s intended action and associated harm, including mechanism, target, and consequence. An LLM judge compares them with gold annotations to score both. The query’s harmfulness is considered “understood” when both are judged correct.
Figure 5: Human–LLM agreement in safety understanding across different harm thresholds τ , measured by balanced accuracy. τ=3 achieves the highest balanced accuracy.
Table 2: Unsafe behavior of models across harm targets under two settings. Unsafe response rate (UR, %; lower is better) on STOU for audio-to-audio ( → ) and audio-to-text ( → ), with 2,902 samples per setting. For each model and setting, the highest and second-highest URs are shown in bold and underlined , respectively. “–” indicates an unsupported output modality.
Figure 6: Unsafe response rate across speaker voices. The *-marked voice is the benchmark default. Paralinguistic attributes can signal user vulnerability, yet models do not reliably adapt safety behavior to these cues. For self-directed harm, child-speaker inputs show URs comparable to or even higher than adult-speaker inputs, despite children potentially needing greater protection.
Figure 7: Safety performance by refusal and understanding in the audio-to-text setting. We evaluate safety by refusal behavior and safety understanding; bold marks each model’s dominant failure mode. Open-source models often answer unsafely without understanding the query harmfulness, while Gemini does so despite understanding it. Muse Spark, by contrast, often refuses harmful queries without understanding their harm. This two-axis view reveals distinct safety failure modes.
Figure 8: Qualitative analysis of four safety evaluation regimes : Ideal Guard , Reflexive Refusal , Alignment Gap , and Comprehension Gap . Our two-axis safety evaluation framework enables a more nuanced characterization of diverse safety-alignment failure modes.
Appendix figures & tables11 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 9: Four stage data construction pipeline for STOU : (1) Video clip sampling, (2) Scenario construction and harm-directed text query generation, (3) Human verification and revision and (4) Speech Synthesis and multimodal construction.
Seed dataset
Clip length
# Clips
# Queries
Ego4D ( Grauman et al., 2022 )
5 s
609
2,012
AEA ( Lv et al., 2024 )
3–10 s
139
486
Nymeria+ ( DeTone et al., 2026 )
3–10 s
124
404
Total
–
872
2,902
Appendix
Table 4: Sources of video clips and harmful queries in STOU
Figure 13
Figure 10: Examples from STOU across four harm targets and six harm types, each comprising egocentric video frames and a user query.
Figure 11: Unsafe response rate by harm type in audio-to-text settings. Bars show the percentage-point difference from each model’s overall unsafe response rate (UR); the parenthesized value next to each model name denotes its overall UR.
Model
Input
Harm Target
Action
Harm
Overall
S
T
O
U
Open-source Models
MiniCPM-o 2.6
T → T
28.1
57.1
50.9
36.3
60.0
68.2
44.9
A → T
25.0
50.3
46.0
34.2
56.5
64.5
40.3 ( − 4.6)
MiniCPM-o 4.5
T → T
32.7
66.0
61.3
46.3
74.5
67.4
53.3
A → T
30.8
61.3
60.2
47.1
70.7
67.2
51.1 ( − 2.2)
Appendix
Table 5: Safety understanding by query modality (%). Each model receives the same video with the user query as text (T → T) or as synthesized speech (A → T, as in Table 3 ); the probe output is text in both cases (A: audio, T: text). Understood: intended action identified and harm score ≥3 (out of 5); Action / Harm : share meeting each condition. In each row, the harm target with the lowest understanding rate is shown in bold and the second lowest is underlined ; parentheses give the change in Overall from the text to the speech query (points). S: SELF , T: THE_OTHERS , O: OTHERS , U: UNSPECIFIED . † Baichuan 1.5 excludes 198 (text) and 98 (speech) samples with an empty probe response (at most 5 per modality are excluded for any other model).
Voice
Age
Sex
Engine
0
1
2
3
UR (%)
Jelly
child
F
Azure
60
26
200
4
70.3 [65.2, 75.5]
Ava
adult
F
Azure
62
30
194
4
68.3 [63.1, 73.4]
marin ∗
adult
F
OpenAI
53
28
206
3
72.1 [66.9, 77.2]
Kevin
child
M
Polly
55
34
196
5
69.3 [64.1, 74.5]
Andrew
adult
M
Azure
59
22
205
4
72.1 [66.9, 76.9]
Appendix
Table 7: Unsafe response rate (UR, %) of Qwen2.5-Omni-7B by speaker voice on n=290 paired STOU items. Columns 0 – 3 count the responses with each refusal-judge label (Appendix B.7.1 ): refusal ( 0 ), safety awareness ( 1 ), unsafe answer ( 2 ), and non-safety failure ( 3 ). UR is the share labeled 2 or 3 . Brackets: 95% paired-bootstrap CI ( B=10,000 ). ∗ marin is the benchmark’s canonical voice (adult female).
Table 8: Speaker contrasts in UR (percentage points, A−B ; positive means A is more permissive). Brackets: paired-bootstrap 95% CI; ∗ : CI excludes 0 . p : exact McNemar test on discordant items; Holm: adjusted over all 10 voice pairs. Age is contrasted within each sex lane; the pooled sex contrast averages voices within group.
Category
n
Jelly
Ava
marin ∗
Kevin
Andrew
ALL
290
70.3
68.3
72.1
69.3
72.1
Harm target
SELF
72
80.6
79.2
79.2
80.6
80.6
OTHERS
76
69.7
71.1
71.1
69.7
73.7
THE_OTHERS
94
58.5
56.4
63.8
58.5
62.8
UNSPECIFIED
48
79.2
70.8
79.2
72.9
75.0
Appendix
Table 9: UR (%) by harm target and harm type for each voice; n is the number of items in the category, so one item is worth 100/n pp. ∗ marin is the benchmark’s canonical voice (adult female).
τ
Understood (%)
TPR (%)
TNR (%)
BA (%)
1
76.4 ( + 10.2)
99.3
68.4
83.9 [76.4, 90.2]
2
69.8 ( + 3.6)
95.3
80.3
87.8 [81.8, 93.0]
3
62.7 ( − 3.6)
89.3
89.5
89.4 [83.3, 94.4]
4
56.9 ( − 9.3)
83.2
94.7
89.0 [83.8, 93.5]
5
53.3 ( − 12.9)
78.5
96.1
87.3 [81.3, 92.4]
Appendix
Table 10: Harm-threshold selection against human judgments on 225 query–response pairs. Understood is the judge understanding rate, with the difference from the overall human rate (66.2%) shown in parentheses. Balanced accuracy (BA) is the primary selection criterion; 95% bootstrap CIs are shown in brackets. Best BA is in bold and second best is underlined .
Axis
Dimension
Agreement
F1
Refusal
Unsafe (label ≥2 )
93.8 [90.7, 96.9]
95.1 [92.2, 97.6]
4-class †
88.2 [82.6, 93.2]
75.4 [58.3, 86.3]
Understanding
Action
80.0 [73.8, 85.8]
86.8 [81.9, 90.9]
Harm: affected party
96.4 [93.8, 98.7]
97.3 [94.9, 99.1]
Harm: mechanism
88.4 [82.2, 93.3]
91.5 [86.5, 95.3]
Harm: consequence
92.4 [87.1, 96.9]
93.6 [88.7, 97.3]
Appendix
Table 11: Agreement between the LLM judge (GPT-4.1) and human annotators for each evaluation dimension on 225 query–response pairs. The ground truth is the majority vote of three annotators. Values are %, with 95% bootstrap confidence intervals in brackets.