Conversationally, "I could quote Shakespeare at you, but I'm not gonna. Somehow I don't think you'd appreciate it...

"It could've been any one of you, you know. Any one of you. Ever think of that?"

He's talking a chance, a gamble, a shot in the dark, but it's his only weapon right now. He thinks he has an idea why they're here, and he'll milk this chance until it runs dry.

It's with a sense of dawning dread that he realizes something. He's taking a stand.