[dragnet2]

The old guy was in shock by his own actions. That was inordinately clear. Hard to believe, but it happened here.

You’re right he pulled the trigger. Even apologized to the suspect who had just minutes left to live. The suspect is dead, the officer will never be the same in this case. No winners here. A collosal deadly mistake.

[Shimmer1]

The officer will never be the same. Well darn, isn't that just sad!
I'd say the man he just killed will never be the same, not "oh well, colossal mistake, gee whiz. Too bad" Which may not be what you mean, but that's what you sound like you mean.