I believe i just found another Exploit working for this fight (and probably this fight only, since you need your enemy to have quite low HP) ...
Often, when you attack from great distance, you dont get into combat imediatly but there is small window in real time.
It also takes few seconds before enemies start heal themselves ...
So if you attack again (and sometimes even third time) and are lucky enough to not miss in any of those cases, sometimes you manage to kill one of them before combat even starts.

(In tutorial i was able to kill all 3 Imps before combat started after meeting Lae'zel)