Wouldn't be altitude since it was at sea level, but maybe air pressure due to temperature? But, at sea level, seems like he'd be cutting it way too close regardless.
That's just... such a marginal thing. It's like complaining your supercomputer melted because the CPU got 0.1C too hot. Like - it's technically possible, but if it's that close you were already way way way past safe and sane margins.
