No. The key looks strange and I hab to reread it a few times. I’m also quite certain I have seen the same joke before in a different comic

The ghost is sad because it locked itself out/forgot the key inside. Second ghost shows up an tells them to just warp through because they are ghosts. But instead of being happy they are inside and never needed the key, they try to move the key outside so they can unlock the door to get inside.

And the brain didn’t even know it was naming itself.

The ancient Egyptians removed the brain before mummification because they considerd it to be basically useless. Later associations between motor control of muscles and the brain were discovered but it wasn’t until the development of modern neuroscience that the brain was considered to be the seat of awareness, self and intelligence.