Accidents happen.

Poor Simon had an unfortunate run-in with his door and tore his 'thumb' nail to the quick.  If you ever find yourself in need of stopping bleeding, plain corn starch will act as styptic powder and is safe to use on bunnies.  His nail wasn't even long, it was just dumb luck how he placed his paw.
So, it never hurts to keep bunny first aid supplies at the ready and common pantry items can fill that need.