Eggsy definitely knows better than to eat these things, based on literally every experience he's had at Duplicity, but he's never been really good at listening to his own better judgment.

"Sure, why the hell not," Eggsy says, taking one of the biscuits. It's small enough to eat in one bite, which is great when you're not sure about it in the first place. No point in biting it in half, so he doesn't. He just eats the whole thing and prays it doesn't make him blind.