A fascinating story.
I’m not too good at identifying doors, especially rectangular ones, and especially from the “janitor’s side” (outside). Mosler would be a good guess. Here are others with a similar pressure system:

The above is in Cincinnati. A close match though the crane is different and the hand wheel is larger.

The above are in Lead, South Dakota. Another near match, the crane seems to match as well as the finials. The pressure system is basically the same but differs in details.

The above is in Colorado Springs. This one is a Diebold door but used the same general design. The hand wheel is centered (left-right) and the finials are definitely different.
Mosler usually put a serial number on the boltwork operating handle, which seems to be missing on the Vanuatu door.
It would be great to see the other side of the door even though it’s probably in heartbreakingly bad condition.