I'm pretty sure that scene is one of those built-into-the-game scenes, meaning it plays randomly no matter what you have or have not done. I've watched that scene many times from the same game save (so nothing that happened earlier than this scene is different), and sometimes Irvine misses and most of the time he gets it in. It's probably just programed so that the game seems more lifelike in that the exact same sequence of events doesn't always occur. But interestign idea, nonetheless. I hadn't really thought about it before.