Most likely, Gregor will open the door or someone in his family is going to force the door open. This will reveal Gregor's new form and the reader will get to see how Gregor's family reacts to his sudden transformation. Most likely they will be shocked and afraid at first.
Answer:
"Never forget what you are, for surely the world will not. Make it your strength. Then it can never be your weakness. Armour yourself in it, and it will never be used to hurt you.”
The rock pile is a dangerous place the parents can't protect their kids from.
Hope this helped :)
-Warning2
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