My hospital happens to be two Z-levels below the surface. I dug a short tunnel from the hospital entrance to one side, then a 4x4 pit, topped by a retracting bridge. The top of the pit is surrounded by walls, with a door. It's designated as a burrow called "Guinea Pigs."
I take a few newly arrived migrants — ones with no friends — and turn off all their labors and give them the custom profession "Patient." Assign them to the burrow, lock the door, pull the lever.
They drop two Z-levels and land right outside my hospital waiting room … which is also a meeting area. Lots of moderately debilitating injuries, like compound fractures. Good practice for all medical specialties.
The risk, of course, is that I'll cause a spinal that leaves a dwarf paralyzed. Out of the first batch of eight, I got one with a broken spine. I tried to mod my dwarves to heal nervous tissue, so we'll see if he recovers from it. I hope he does, because this time out I was lazy and neglected to build my hospital beds inside automatic drowning chambers. I suppose if he's a permanent invalid I can always wall off the area around his bed and wait for him to die of dehydration.
Oh, helpful hint: The hospital must also be in the "Guinea Pigs" burrow. Otherwise the walking wounded won't go there themselves, nor will the haulers recover them.