I wasn’t nesesarily bothered by the scene. I quite liked it actually, i was simply putting in my 2 cents. In the situation it could make sense for them to drop to instinct due to trauma.
Thinking about it now my perspective may have differed from what the mc might think. I was thinking about it from the training perspective that i have, which was that under no circumstance do you ever point a weapon at anyone unless you intend to kill them with it. (ie essentially never) Whereas a hunters training probably would have been to get ready to fight and possibly kill with your weapon. (i presume they would also get safety training but possibly to a lesser extent then combat itself)
Perhaps it would we simpler (and also make perfect sense) to simply make it that the mc is startled and goes into flight or fight more clear. (as @tiranka has already mentioned) perhaps having Lupa do something which might cause a bit more of a startle?