On the freefall time, the 3+ minute estimate is a bit off.
s=ut + 0.5at^2, assuming an initial vertical velocity of 0, and initial height s=8000m (I can't be bothered to convert 35,000' to m), t would be around 40s.
Based on the assumption the aircraft continued to accelerate in a uniform manner all the way down. That equation (better expressed as v^2=u^2 + 2as) gives a velocity after 8000 metres descent of 396 metres/sec or approx 900mph. Is it reasonable to assume that kind of velocity could have been achieved?