This part of the level isn’t a terrible place for an ammo box, there are more ammo spawns in the sunken room and you probably need ammo after running the gauntlet to get to this point.
However putting the box right in the middle of the corridor is bad. My party had to fight a horde from two directions at this location and we kept getting stuck on the box when trying to move past it in either direction. The box should be over in the corner instead.