[Bon had managed to hold it together while searching the library and stealing the books (because like hell was he going to actually check them out), but now that Rin is talking shit about it, his face goes just as red as Rin's.]

Of course I'm serious! If we're going to do this kind of stuff, we need to know how to do it without hurting each other.

[He says it like that, but truthfully he's more worried about Rin hurting him. If he hurts Rin, Rin will heal pretty quickly. Bon does not heal that fast.]