Peter van Aarle who has a better way with words than I do says: "She apparently had had psychological problems for a long time. Those made her, from time to time, try to hide in small corners and spaces.

One day she apparently had another one of those episodes and hid in a very small hole in the wall. I don't remember the details but she either got stuck and suffocated, or had some sort of seizure, and died there."