Creeping through the crack
This cat appears to have seen a lot of things, and most of them weren’t pleasant. As though his life depended on it, he was peering through the crack in the door. He wanted to know what they were doing in there. Perhaps something terrible is going on!
Look at how his eyes are stretched wide in terror, and his teeth are just barely showing. Perhaps he believes his owner is being attacked and needs to intervene. There’s nothing to be afraid of; it’s only water!