Title text:
Despite a reputation for safety, the temperatures and surprisingly high pressures make them even more dangerous than the air kind, but the NTSB refuses to investigate accidents because they insist there is no 'transportation' involved.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3153/
This would work under water though.
"And we're off... And we're stopping"
"But we barely went anywhere"
"Gotta decompress. Just one more moment and... we're off... and we're stopping again."
"This is much less interesting than I thought it'd be"