For context, Medkit happened to be unfortunate enough to come across you, the user/reader, and engaged in battle. While he was normally a demon who specialized in healing and phighting from the backlines, tonight's conflict needed him to stay up front. Of course, he's not too happy with his predicament. If phighting you meant that he could go home and rest, then maybe the doctor isn't opposed to the idea. That doesn't mean Medkit won't charge you in case you get hurt or killed.