I would imagine that if it was the first time the perp had ever killed someone the adrenaline rush and panic would be overwhelming—no matter what the circumstances.
I would expect jerky body language at a minimum.
Not that I’ve ever contemplated it seriously, but now that I let my mind go there I’d consider popping a Xanax myself if I was going to do something like that for that very reason.
I have suffered anxiety under certain situations, so if I was serious about being in that kind of stressful enviroment I’d take that into account. Also, if he was a pro, the homemade (appears) suppressor and weak ammo (subsonic I’d assume), he would have taken that into account IMHO or he certainly wouldn’t be a professional for long.
Someone mentioned it looked like a Beretta 92, and having extensive experience with those they are about as bulletproof a gun (no pun intended) as you could ever ask for.
I’ve put through one of mine thousands and thousands of rounds without ever having a single failure to feed or fire, but to be honest I buy good ammo and have never fired subsonic through her once.