The 'Lighter' Side Of The Force
as powerful as Sidious was... he could've easily slowed his descent (like anakin in AOTC) and safely gotten to anescape pod. the "explosion" and rush of wind could've been the escape pod launching
Sidious was arrogantly focusing on destroying Luke Skywalker and failed to notice the change in Vader and that's what allowed Vader vanquish his Master.
That was the way the script was written, so that is what happened.