“Not the first time this character has chimed in. “
Yeah some of it sounds believable but he is not very smart and thus mixes in some stuff that gives it all way.
For example he describes scenes that took place after he took his shot. After shooting a President he would not have been standing there watching. He would have quickly left and not seen Jackie crawling on the back of the limo and the motorcycle cop walking up the hill where two guys in suits show their ID. Thus he gives it all away because he doesn’t know when to shut up.
Don’t discount personal curiosity overcoming survival moves.
Running away at once would attract attention.