I walked by her several times, not paying any attention.
I heard her wailing a bit at first, but she looked like she was having fun, so I assumed it was part of the game. After 15-20 minutes of this game, I realized she was oddly quiet. But she was fake-sleeping.
Apparently, she was trying to pick up the pillows but staggered backwards, landing with them on top of her. She assumed it was too heavy to get out from under and thought herself stuck. She enjoyed the drama of being stuck. She especially enjoyed the attention we all gave her at the end.