Derek strides into the wardrobe room and demands to see Marilyn's costumes. He starts holding each dress out in front of him, seeing first Ivy, then Karen, dressed as Marilyn in the fantasy sequences we've seen all season, and appears ready to make this million-dollar decision based on which bodice he imagines filled out best. This is why there are so few straight men in theater.
Stage Manager Linda calls the company to the stage. Derek comes out on stage and calls for Karen. He tells her she's going on as Marilyn in, oh, eleven hours. Everyone tries not to look at Ivy as she swallows back a whole bunch of vomit.
Linda asks Derek if he really wants Karen to go on tonight, and protests that none of the costumes will fit her because Rebecca's a foot taller. (I do not think that is true.) Derek tells her to find one dress that fits. Karen is going over the songs with Tom and Julia, who is controlling her panic admirably, and being amazingly un-twattish compared to her behavior these past bazillion weeks. She tells Karen that everyone loves her and wants her to succeed, which proves that Julia is still delusional. But as she hugs her she makes an insane freakout face at Tom over Karen's shoulder. Tom bugs out his eyes in response. Julia asks Karen what she needs, and Karen, of course, asks if she can call her fiancé, because she is a mewling brat who needs her hand held every second of every damn day and I know this is a stressful and unusual situation and all your dreams are coming true but at the same time you're terrified down to your very fillings but oh my god, SACK UP, HO.
Derek calls Karen to get to work and Julia screams, "She needs to make a phone call!" the same way you or I would scream "That baby just fell out the window!" Julia takes her concerns to Derek, who insists that the show is going on with Karen tonight, and redirects Julia and Tom to the new song.
Karen tells Dev, who's back at the grubby cast hotel, that she's playing Marilyn tonight. She asks him to come watch her rehearse. Out in the seats, Ivy is watching grimly, dreaming about how maybe stupid Karen will trip and fall into the orchestra pit and break her skinny Iowa neck and then Momadette Peters will finally see, she'll see that Ivy has talent, all right! Ellis, whose guile has deserted him in this time of frantic worry, meebles over Ivy's shoulder, "I can't believe this." Ivy adds him to her mental list of first up against the wall when the revolution comes and gets up when Derek calls the shadow selves to the stage.