Tips for killing enemy crew without use of boarding parties
While playing FTL, one of the jumps resulted in me picking up an angry spacer whose ship had just been captured by pirates. He requested my assistance in retaking his ship which, he stressed, would entail not destroying it.
I had no crew teleporters so I proceeded in destroying the enemy ship's oxygen supply subsystem until the oxygen drained to below 5% (I know this because I got the achievement). I waited a while and... nothing. I realized they might be healing so I also disabled the medbay as well. Waited a while and... nothing. I didn't have scanners level 2 so I didn't know for sure what was going on but all the enemy crew must have died, no? In any case the ship kept firing and I was eventually forced to destroy it, much to the dismay of the spacer I picked up.
Was there any way to complete that mission successfully without me having any crew teleporters?