I've been told...

but have never really thought it, myself lol... But, yeah, you're dead on: you can't move more 3-5mph, at most, underwater.. Its kind of a situation where if the sea critter makes a move, you're toast - there's really nothing you can do.. So, I look for the signs and keep the camera rolling.. if I'm gonna get bitten in half, I'd at least like to make an episode of Shark Week lol

---

Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..