Yeah, the 3 sec rule for mens college hoops is unique to other levels & genders as far as I know.. The rule was well-intentioned when first implemented, trying to keep the Mikans & Chamberlains from simply camping out 2 feet from the basket. It was also (IIRC) created pretty much in junction with the widening of the lane. Look at old clips of basketball in the late 30s & 40s. What came to be known as the 'paint' was really, really narrow.
Anyway, the suspension of the 3 second count by lifting the foot only works if the other foot is outside the lane. I suspect the Purdue staff are masters at ingraining stuff like this, since they've done so well at developing big men to their advantage. And I guess part of it is knowing what you can get away with, because as you said there's so much going on the refs aren't going to see everything. If you google "college basketball 3 second rule" there's some stuff that specifically mentions Edey & explains it pretty well.
Don't get me started on batters standing there crowding the plate with their padding & body armor. I give credit to guys like Don Baylor & Ron Hunt, who would at least take one for the team without being layered up like they were training attack dogs.