After retrieving the files, they escaped over a wall to an awaiting truck near Bang Sue Junction. A media team noticed the men, who alerted authorities.
The 33-story under-construction building came crashing down in seconds during a 7.7-magnitude earthquake that struck central Myanmar.
The skyline of the megacity had been dotted with cranes, and no other construction site reported similar collapses.
The mishap sent a cloud of dust and debris into the air and trapped dozens under the rubble.