Suspect's subjective knowledge of whether he is encountering police is not relevant, but question is whether an objectively reasonable officer could conclude, that suspect knew he was pursued by police; deadly force was reasonable where subject was suspected of involvement in two violent felonies where bystanders were threatened with a gun, fled police, ignored warnings to drop his gun, ran around corners where it was possible to ambush officers, had gun out, and picked up gun repeatedly after being told to drop it.