You 'll notice there are 3 patches of blood, gore and guts (yummy) where the Crawlers spring from. The trick is to get the surgeon right in front of the staircase. By doing this, it will only be able to use 2 crawlers because the third one at the far end of the room will be too far away. And those crawlers in question won't be able to see you and engage you. If you're in a party, set all archers and mages to damaging the surgeon from above, near the energy pillars and have your melee fighter attack the surgeon and kill the crawlers when they come next to him. Any melee fighter can take out 2 crawlers in no time. Just make sure you lose the shield if your melee fighter is s/s, because Rebuke pushes the crawlers away which is definitely not what you want, since you'll waste time.
I always go solo, but I reckon you 'll need lots of healing potions (or healing rain?) for weaker party members to deal with the "Doomsday" curse that the 2nd surgeon casts. Your melee fighter won't have any trouble with some decent life leech.
After you 've dealt with the surgeon you can kill off the remaining idle crawlers at the back of the room. Don't be overwhelmed, there will be *lots* of them.