I suppose that some fathers may do this— and perhaps others may believe it “okay” when they see a good guy do it in a movie. THE REASON that I write this is to warn that “slip-and-fall” injuries in the shower are a common event in households nationally— usually the injury is minor to an adult alone who slips. HOWEVER, this would NOT necessarily be so when an adult slips with a baby in his/her arms.
DO NOT TRY THAT AT HOME!
INSTEAD: Use an appropriate and approved baby bathtub, with a built-in, “slant-sponge” surface so that the baby cannot accidentally slip underneath water, even if the little one becomes completely un-handed (let go of completely). Place the plastic baby bathtub on the floor, upon thick towels, so that even if your little person manages to slip/roll out of the tub, (s)he lands on a towel-cushioned surface inches away, and there is no possibility of rolling off a counter or table into a drop long enough for serious injury.