Question (spoiler alert)

First off, I think this movie is brilliant and have seen it multiple times. However, rewatching it after a few years, I wanted to see if anyone else felt the way I did about something. When Mark Boone Jr.'s character (the snow plower whose name escapes me and I've already begun writing this post haha) is using a bladed machine to kill vampires in addition to using a shotgun. This seems to be working well, until he crashes the machine into a building. I personally couldn't hear the movie very well and didn't want to turn it up too loud where I was watching it, but was there a reason he crashed through that building as opposed to continuing his killing spree? I know he had the explosives, but it seemed like he could've kept going with it, especially if he was going to attempt killing himself in the explosion. There's also the possibility he didn't realize how small the explosion would be, but I just wanted to see what you all thought about it.