I'm sure something could be worked out. Get the werecreature in a locked room, have Urist McCripple in the next one, with a hatch (opens instantly) in the tile where the werecreature will hit him from, then as soon as there's one bite, pull a lever, dropping the werecreature away from Urist McCripple. Something like that, anyway.
You would have to pull the lever before the were-creature bit the poor Dwarf.
Hm, true, since I'd have to amend the previous to use a retracting bridge, since open hatches don't actually make creatures fall through, just let them path through it. */brainfart* The time delay could certainly be worked out as well, though. Probably safer to have the 2nd room be a hallway, with a pressure plate that the werewolf triggers so it just has time to attack Urist McCripple once or twice before falling down a level. Then a long path looping back to the top, so it'll try again, until you block the original access (once successful, or Urist McCripple gets killed). I never said it would always work, but if Urist McCripple was previously Urist McLegendary, would you rather have him lie in a hospital bed for the rest of his life (=until someone forgets to bring him water), dump him into magma, or have at least a small chance to make him into a werecreature, thus making him fully functional again, and ensuring that he would also heal from all future wounds as a bonus?