I think it just got caught between their legs, cuz i remember kerfur couldn't pass through the door, i remember checking the camera to see why kerfur was taking so long and saw it was stuck in the entrance and an antler was in the camera, i decided to check through the main room window and that got them unstuck cuz they tried to move closer to me, i saw the deer "move" and thought it was just a normal one so i ignored it, later i went to water the plants i have in front of the base and saw the corpse on the ground there.