The action itself is easy. Just find security guard Harry and read his mind when he's unconscious.
How to get him to appear in that state:
In the Asylum chapter, after you've pasted the Good Chart (found to the far left of the asylum level) into the tunnel digger's mind, he'll break into the asylum and alert the security to send in Harry who will take the digger's place in the tunnel.
You have to then finish the tea set in the giant pink bunny's thoughts and paste the tea set onto the tea party table in the underground room with the bedraggled teddy bear and coffin.
The coffin will then open to reveal a ghost girl and the bunny will be attracted by the smell of tea.
The bunny will walk over to Harry who will be scared out of his wits and faint as the ghost girl tackles the bunny into the ground.
Read Harry's mind then to get the trophy. (Easy, right? ;p)