I would trust a revolver over an auto for shower duty. A beater Smith 642 would seem like a great little gun for the task, but I would still take it out of the shower and wipe it down and spray WD-40 and Rem0il into the internals and let it dry out good. Shower steam is wicked on a gun, and a friend of mine learned that the hard way about a year ago. He said he had two old S&W .38s he wanted to sell and I wasn't really interested at the time, until I saw one. It was a mint condition 1964 M-36 Square butt 3" barrel in the box with tools and papers. The factory paper crackled when I took the gun out just like the day it rolled off the assmbley line in 1964, and I don't think the gun had ever been out of the box since the day it was purchased. I quickly bought it for $310 and he said the other one was just like it except it was a 2" nickle plated gun at his mothers house. I saw him a couple of days after he went to his mom's house and he pulled out the S&W blue box and removed the lid. His eyes got as big as saucers! The gun looked like it had been lying on the bottom of the ocean for a year! It was totally corroded and deeply pitted and looked like it would never fire again. He said he stored it in a cabinet next to her shower when his own house was being remodeled.