1 Jamie: We're going to submerge Adam in this tank of water, bolt the lid on, and see if he can escape.
2 Adam: So what are the safety precautions?
3 Jamie: There'll be a scuba diver with an air tank...
4 Jamie: ... chained up in the tank with you!

I've done some snorkelling in a few different places around the world. (Not scuba diving, just snorkelling.) It is very cool and I've got to see all sorts of colourful fish, sea urchins, sea lions, and even a couple of large sea turtles. I highly recommend this as a holiday activity if you ever get the chance, even if you're not normally a water person. It's a truly eye-opening experience.