The context of the following conversation is Ash went to kill Addison, so he got a giant knife and some sneaking shoes.:
Ash says Addison has the role of Marion in the play based on the Hitchcock film.
The friend responds And you, of course, are Norman.....
Ash responds Of course. And she has triggered my psychotic murderous impulses.....
The friend responds And Marion is now in the shower.....
Ash responds Yes, and I have my sneakers on so she can't hear me over the water.....
The friend responds OMG, whose nutty idea was it to turn Psycho into a play?.