Its a room with 1 exit. A single exit.
After you type flee three times, and have fled out, you should already be finished typing dash w pincer tli
You might have been able to kill him with a lucky deathblow or two.
One exit rooms, cabal outers, places like that are amazing for abusing dash.
Dash is the single best warrior skill in the game, in my opinion. Don't undervalue it.