FlapsOne, I agree with you about the speculation, and I don't know the details. However, Maxy makes a valid point.....and of course when opening and closing the door of a 737 using airstairs, you need to disconnect the top of the railings from the aircraft, leaving a nice little gap on either side. This incident has highlighted this risk, and fellow pilots should be aware and be careful.
Our thoughts are with him, and hoping he has a full and speedy recovery.