Cheat the system by launching into a monologue that doesn't contain any full stops and is in fact one sentence, whilst dressing the wound and calling an ambulance/walking to hospital. Job done.
Alternatively, look him straight in the eye, and say "Your mother would be so disappointed, Adrian." It probably wouldn't work, but if the killer was in fact named Adrian, the look on their face would be priceless. And if not, at least it would leave them confused.