Renwick And Moth Do Some Math
Renwick, these Knights definitely don't bleed. In fact, when the flamethrower Knight drops, it just collapses into an empty suit of armor! Maybe it was possessed by a ghost or something, or maybe it's some kind of golem or automaton. Or maybe just a crazy form of metal life you've never even heard of before!
You're a smart guy, so I'll assume you'll waive that Sleep spell then. Magic Missile shot off, then. DINK.
Moth, if you can make combined DX and IQ checks, you can find a blast angle where you won't hit PCs or damage the Tart. You'll have to try each round. Failing that, you can always bandage Schmektor to keep him from dying. [NOTE: We play that when unconscious (-1 to -9), you drop one hp each round until 'bandaged'. When you hit -10, you're dead. Steve, Schmektor's PC, once had a cleric in a table top game I ran who went all the way from -1 to -10 in ten rounds and died without anyone bandaging him, so it might be a sore spot with Schmektor.]