Main exit is located right by the gift shop

We'll take a stab here.

Semi-cramped and uncomfortable after two hours of sitting, the final crescendo of group sing awakens you from your half-slumber. Moments later when the cast comes out for a final bow you are so excited to run out and use the bathroom that you leap to your feet and applaud heartily nodding enthusiastically to bring the blood rushing back to your neck and shoulders. Then the lights come on and your partner, who bought or was comped the tickets, turns and doesn't ask, but says "Wasn't that wonderful?" To which you can only agree and say it was by far the best show you've ever seen, and thank you so much for thinking of you. As you file out with the rest of the denizens you are sure that you will be the very last person to exit this theatre. Above the happy chatter and plans being made for apres-show cocktails that surround, you hear your partner's voice, asking "Can we just pop into the gift shop? Give us a chance to let the cab line die down." You mouth "Bathroom" and after waiting in line for 10 minutes, reprieve is yours and you are now thinking about that cocktail, and maybe the show wasn't THAT bad. The lobby is surprisingly empty and you find your partner waiting outside the restroom, by the water fountain with one leg propped up against the wall. A plastic bag is thrust into your hand, "Here, I didn't know what size t-shirt you were, so I bought you this souvenir. Everyone needs an umbrella."