I agree that it’s strange to see the locking bolts on the outside. Here’s a construction image showing the mechanism:

Notice also that the door is part of the electromagnetic pulse (EMP) shielding. There is a large braided-metal grounding strap on the outside that electrically bonds the door to the frame-side hinge, at the bottom. The inner face of the door also appears to include flexible braid that presses against a polished surface of the frame.

Clearly a heavy-duty door similar in some ways to bank vault doors but with a different set of requirements and threat model.