I'm skeptical, how did a memory card survive such an impact?

The flight was at 10am. Everyone with window seats would have been able to see that they were about to crash-land in to the mountains. Plus it was an airbus, not a jumbo jet, so it's possible some of the passengers closer to the pilot's cabin would have been able to see him bashing on the door trying to get in while pleading for help.

They would have known something was seriously, seriously wrong.

You've experienced a nose dive?

devastating

There was one aisle, everyone would have been able to see and hear the pilot screaming to get back in. Think about any domestic flight here, even if you were sitting in row 29, you'd still know if someone was banging on the cockpit door