It would seem that just the speed of these spinning would rip and tear at a body, if they were swept up into it. These things were peeling hoods and tops of cars off like a can of sardines...the body then would not be able to survive that force.
I listened to a professsional storm chaser , who actually has a vehicle designed to go into a tornado. When he explained the shaking of the vehicle and the force against it that pretty much answered my question too. He said he’s done this about 6 or 7 times now and still is afraid when the tornados start traveling over his vehicle.
The human body can actually survive EF-5 winds just fine; it's not that different from what skydivers experience at terminal velocity. It's the debris - even granular debris like small chunks of roofing shingles - that kills. Wind at 200 mph won't kill you, but nails and shingles and bricks at that speed will.