[colebowl]

That door has no handle, no sign of a swipe card reader. Any ideas how the people who can would get that door open?

My guess...some kind of reader hidden in the door that triggers a mechanical device that lifts the panic bar (another comment's comment) or otherwise disengages some such other locking mechanism.

[doublerabbit]

My guess is that they just use noclip and walk straight though.

[cantrevealname]

My assumption is that this door is an exit — perhaps an emergency exit with a push bar. The room is big, 1152 square feet according to the article, so it probably has a real entrance somewhere else which couldn’t be photographed.