Thankfully he never got the chance to act on it, and stopped himself before he could. It's interesting though, we're in a subreddit where a lot of people probably love revenge movies, able to cheer on that protagonist goes on a murder spree and kills all the bad guys, presumably because they understand or identify with him/her. Yet when we read about real experiences of anger, we act like the person has some unknown disease. Real life isn't like the movies, but in this case only in the sense that the anger doesn't always get directed perfectly at the bad guys, but it still gets felt, it still has to go somewhere. You don't have to excuse it, Neeson clearly doesn't, but we can at least acknowledge we understand it.