6,000 feet in five minutes doesn't sound terribly extreme. 1200 feet per minute, 20 feet per second. That's not even 1 G.
Such holes in the air aren't uncommon. A had a cousin who was a flight attendant for United Airlines. He was badly injured when a flight she was working hit a hole in the air and she struck the cabin roof, then the deck. It was months before she was able to return to work, she continued to have back problems, and she eventually took a medical retirement.