I don't know if it was going 140 at the moment of impact (I've seen Cars torn in 1/2 and the pieces 100 feet down the road that couldn't reach 100, let alone 140), but if that was the only tree they hit and the car was still wrapped around it, the odds are very high the decelleration alone would have killed them (even if they didn't hit anything inside the car).
The human body isn't made to withstand 140 - 0 in 5 feet. It would be like jumping out of an airplane, without a parachute.