Joseph takes a shower

Joseph has started to have selective separation anxiety. Most times he is fine being left to play by himself and could care less if anyone he knows is around. But for some reason every time anyone gets in the shower he freaks out. He has a sixth sense about it too. He can be in another room and as soon as he hears the shower turn on he stops whatever he is doing and gets as close as he can to the offending person. It started with my dad, if Joseph saw him going upstairs to shower Joseph would zip up the stairs after him and stand at the bathroom door screaming until he was done. He does it even if someone else is around. Whenever Jared or I get in the shower Joseph will be at the shower door. If the other person tries to distract him he usually wants nothing to do with you. The part that make me really laugh is if you bring him into the shower with you he screams as well because he doesn't like the water splashing him.
Anyway Saturday I got in the shower and Joseph ran over crying that I was leaving him. He stood at the shower door hitting it and screaming he usual bloody murder. After a few minutes I opened the shower door to stick my head out and say hi. Well Joseph seized the opportunity and climbed right in, fully clothed. He sat on the floor of the shower splashing and laughing at how cleaver he was for about 30 seconds before he wanted to be picked up. I scooped him up, stripped his clothes and diaper and scrubbed him down. He didn't really appreciate this but hey it saved me from having to give him a bath. Then I took him out wrapped him in a towel and laid him on the floor and jumped back in to finish my own shower. He was so mad and screamed the whole time but didn't move an inch from where I put him. He never will just lay there in a towel.