It's very obvious that tough guy is meant with a shitload of sarcasm so he doesn't bother to let it bother him.

When he's done talking and his head isn't pounding he actually finds it in him to not try to take Beelzemon's gun again to shoot him with it. Lester just rolls his eyes. Yeah, he's a shitty guy, but he doesn't care. He's always been this way and isn't likely to change now that he's in hell.

Thankfully he doesn't have to share anything else because the doors click as they unlock and he's quick to spring to his feet and make his escape. "Whatever. See you around, shitstain."