When perceiving imminent harm to others, quickly detecting potential hazards to oneself should be vital. In this case, mirroring the outcome of observed actions appears paradoxical. This study measured electroencephalographic/event-related potentials and mu suppression that were induced by dynamic animations; each animation was composed of three consecutive pictures depicting an individual being accidentally injured. The results indicated that the first picture evoked frontal N260 and central N360, the possible brain source of which is estimated in the dorsolateral prefrontal cortex, and the third picture elicited late positive potentials, the possible sources of which might be generated from the insular and mid-cingulate cortex. Differential mu suppression, in relation to the sensorimotor resonance of empathy for pain, is associated with the third picture containing the crucial affective valence, but not with the first picture. The masking procedure on the third picture attenuated this mu suppression. Mediation analysis further confirmed that sensorimotor resonance is not a significant mediator in predicting subjective unpleasantness for observed actions. The findings suggest that sensorimotor resonance is not a platform, but rather an outcome when anticipating harm to others.