seems lobsters can move only when in water!

Not the lobsters I know. I grew up on the New England coast, and as (cruel) kids we used to set them on the linoleum in the kitchen and watch them scoot around. They moved a bit erratically, and weren't exactly speedsters (and went backwards, as they moved by flicking their tails under them), but if you really, really wanted to have a lobster race you could probably rig something up. But it wouldn't be much fun.