This clip was sent in by Robin, who says:

"This is a great lesson in pressure differential.

You may have to look at this a couple of times depending on how clear this is on your screen.

This is a video taken in 6000 feet of water. An undersea robot is sawing a 3 mm wide slit (1/10th of an inch ... remember that width) in a pipeline. The pressure inside the pipeline is 0 psig, while the pressure outside is 2700 psi, or 1.3 tons per square inch.

Then a crab comes along."