Visible crew/equipment: During the campfire scene a Morlock attacks Weena, and drags her off. If you look at the top of the frame, as the Morlock drags her away, the stunt man's head can be seen, as he forgot to wear the head part of the costume.
Visible crew/equipment: The string holding up the "Fire Monster" to make it appear like it's standing upright is seen in a couple of shots.
Visible crew/equipment: Near the start, when Major Allison walks into the room and asks Colonel Martin about the reservations at the club, the boom mic dips into view at the top of the screen.