It would be funny if Rosencrantz meant closet the way we mean closet today. If he were like:
“Yeah, your mom wants to meet with you, surrounded by her dresses and shoes. She’ll push the blouses to the side to make a little space for you to sit on the shoe shelf. It’s pretty sturdy.
I mean, I’ve been in your mom’s closet and it smells pretty good in there. It’s cozy. I like being surrounded by all the fancy clothes. Feels safe, too. It’s hard to be overheard in a closet. All those clothes act like soundproofing.”
And then the entire Gertrude and Hamlet scene is in there, entirely claustrophobic and weirdly intimate.