John McClane vs the Bunny from 'Holy Grail'

mcclane has no access the holy hand grenade.

the two are locked in nakatomi plaza and the bunny is pissed off and hungry. mcclane is allowed his arsenal of firearms from DH1, minus the bombs of course.

mcclane starts at top floor, bunny starts in the lobby and is obviously hunting him. aaaaand go!

is that what he'll do in the face of certain death? probably. its his way.

:edit: damnit forgot to add that bunny has access to the air ducts

Yes its his way to act that way in the face of certain death...(that never turns out to be certain because of the McClane factor). Bunny gets a blessed 9mm round between its eyes and literally gets to know what a TV dinner feels like when McClane kills it, cooks it and eats it.. If it survives that, being blown up, stabbed, being punched out, or anything else that is typical of McClane, McClane may be maimed or worse.

the bunny is capable of flight and instant decapitation. you cant just shrug that aside.

as far as his survival abilities, i think its a safe assumption that mcclane is not capable of living if his head and neck were separated.