He'll be fine. Generally speaking, he shouldn't think you had anything to do with him falling into the water bowl. To his mind(tiny that it is) he may think he jerked back and fell off his "branch" instead of thinking that the big human dropped him.
Being in the water dish underwater is something they do voluntarily for much longer than a few seconds. They're remarkably sturdy.
It's good to see a BP owner who is so caring and worried over his pet. Keep up the good work and don't forget to post lots of pictures!