Teeter totter... hehehe.
So I set the floor to unlock. Since this is a massive glass, it should be able to teeter-totter effectively with my weight.
I run to one side so that the glass will start to tilt, then back over across the beam to the other end of the glass. Each shift back and forth across the glass to increment enough balance so that on a swing upward on the right-side, I'm able to ride the edge and get to the door. Now, given the amount of weight to compensate for that upward lift, it should give me enough time to twist the knob, open that door, and walk through before it starts to sail back down.
ADD: Given the height of the door, and I presume the thickness of the glass floor, I would be shifting back and forth across this floor a few times.