Palahniuk has a very interesting style, one that gets tiresome quickly in his other novels, I hear. It seems to work here though. He repeats lines. The emphasis increasing throughout the chapter. "Tyler's pushing a gun in my mouth [...]" is the first one. We see this idea, or some iteration of this idea repeated throughout this first chapter. We are constantly reminded that the narrator has the barrel of a gun in his mouth. And really, what a way to start a book. Not exactly with a bang, but pretty close.
The second thing that keeps getting repeated is the fact that the building is wired and will explode in ten minutes. The narrator has set this whole thing up and acts like a count down, reminding us over and over that the building is going to blow.
These two repetitions provide tension to this scene. Palahniuk wants the reader to feel stressed right as they start this novel. He wants to stress to be overwhelming. You have two immediate problems with no quick solution--the barrel of a gun in the mouth of the protagonist, while he is in a building that is set to explode in ten minutes.
The two best lines:
"I tongue the barrel into my cheek and say, Tyler, you're thinking of vampires."
"With a gun stuck in your mouth and the barrel of the gun between your teeth, you can only talk in vowels." Not exactly like the animated GIF above, but pretty close.