good ideas above, but:

If the case is polycarbonate (very hard plastic), the hot needle may not work, and will be really difficult to reseal effectively.

Warming the box in hot water might get you partly there, but there could be a danger of hot water messing with the seals and housing permanently. Also, the difference in pressure relieved due to hot air I don't think is enough to overcome the difference in air pressure locked in at 8,000 feet. (approx 60 deg C / 20 deg C = 13% pressure difference, versus ~26% pressure difference from sea level to 8,000 ft). But you might as well give it a try.

Last option that occurs to me -- are you anywhere near a scientific facility where someone has a vacuum chamber? Or even one of those "store-lots-of-clothes-in-a-bag" devices, that operates by a vacuum cleaner?

What you would want to do it open up all the latches on the case, put it in a vacuum, and let it open, and then let the vacuum go.

Aside from this, you might have to ask a friend to take it up in a plane for you... or wait until you're in the air again...