You know, in battle - as in hunting, there are only two behaviors. You are either a hunter or prey. And since you intend to become a real hunter, you must learn to track prey without being exposed.
Do not use any Medical items while in a raid when the quest is active. If you do you will be required to accept the quest again.
If you complete the objective to kill the three scavs without healing the task will still fail if you heal before handing it in. In addition, if you complete the objectives but do not click complete with Jaeger, then healing in a later Woods raid will cause failure of the quest.
Surviving the raid is not necessary for the quest to be completed.
Off-raid healing does not affect this quest.
Drinkable Alcohol is a painkiller that will not fail this quest.