Need post-game help in Act of Misdirection

Alright, I’m just gonna spoiler all of this:

So I wanna get the alternate ending in Act of Misdirection. I need to trick David into not making a contract with me. I know it involves the rat and chelsea bun somehow, but I can’t figure out how to get it to work. When I give the rat the bun it just eats it and doesn’t do much, and I can’t get Sarah to pick up the rat either. Help?

Nevermind, I got it.

For those of you in the future wondering how to pull this off, it involves the rat and the bun and the hat. Hopefully that’s big enough of a hint that you know what to do now.