I see your points but honestly you're gonna miss a lot of shots fighting anything, especially birds in the air. Only way to truly hit them with our current equipment is either forcing them to land or getting the right angle on them with a ranged weapon or magic. Complete retreat isn't something Regina is really wanting, simply because it'd be impossible to outrun birds but it is possible to fool them. A tunnel or basement would actually be perfect actually long as there was another way out.

That being said, the objective actually is the monster the cadets must capture. Monster filled territory isn't the best place to fight, well, monsters unless you got the drop on them. Don't have to fight everything after all.