Let me start off by saying this is all complete speculation...ok, with that out of the way...
I took a look at the ImJayStations youtube account. It seems like most of his videos are him playing with Ouija boards, or staying overnight in an abandoned "haunted" location. Since he's into the clickbait paranormal, and they were thinking of doing an "epic" video...and it happened at Magic Kingdom...here's my theory.
They were planning on staying in the park after closing, getting into the Haunted Mansion, and playing with a Ouija board, or trying to prove there were real ghosts in the Haunted Mansion, or some other nonsense.
Funny thing is that there is already video of a couple of people in Haunted Mansion after close, and running from security. I wasn't able to find anything from a quick google search at work, but I've seen it before. I will edit this post when/if I find the old clip.
Just my theory...seems like it would fit the content that seems to be on his channel already.