why won't Frau Diller leaver her house at beginning of the air raid? what finally causes her to leave?

Frau Diller won't leave her home or her seat because she has beem emotionally defeated by the war.

"As the weeks had worn on, Frau Holtzapfel had not yet begun to recover. When Liesel came to read, the woman spent most of the time staring at the window. Her words were quiet, close to motionless. All brutality and reprimand were wrestled from her face."

Liesel gets her to move with the only thing she has to threaten her with.

“If you don’t come, I’ll stop coming to read

to you, and that means you’ve lost your only friend.”

Frau Diller....... she moves.