What is the limit of human endurance. If earlier it was assumed that -40 c would kill in 5 mins and now we have proof that someone has travelled at -62 c for 5

What is the limit of human endurance. If earlier it was assumed that -40 c would kill in 5 mins and now we have proof that someone has travelled at -62 c for 5+ hrs and with minimal oxygen. Isn't that a black swan like event. Obviously we can't test for these things but we can find limits through such incidences. PS : whats with the downvotes. Do some folks want everyone to parrot the same line?