My sister, Molly, normally can be found hanging out on our living room loveseat, but on rare occasions, she can be seen peeking out from under the piano. I don’t think she views underneath the piano as her safe place, because if she gets spooked, she will run upstairs, slowly creep back down the stairs, sit on the landing, and stay there until she feels it is safe enough to come back downstairs.
I just think that it’s a coincidence that Molly sits under the piano, but Wen thinks that she looks cute under there when she peeks out. It’s kind of like she’s giving you the “peek-a-boo, I see you!” look.