I actually love the blue in your bathroom (what's the color?) but if you don't, I think it'd be fine to bring the master bedroom color in there.

I like the blue too, however, you mentioned beach and nautical. The blue you have isnt exactly right for a beachy look, and that may be why you are not liking it. Try a shade lighter, and something that has a bit of aqua in it for the beachy look.

I would take the color from the master into the bath. Find it color card of it & maybe go one shade darker.