Board Thread:General Discussion/@comment-26408694-20141004142023/@comment-24986099-20141011124315

Didn't you even wonder who I used to be?

This pretty much implies they never knew her. Lapis was completely conscious the entire time she was in the mirror, she could still hear and feel things around her. If Garnet kept Lapis for that long and still used her to open the door to her room.

Lapis wouldn't have fled instantly and probably would have been very angry that Garnet used her, acting on impulse and outright attacking them then and there. Instead she fled and instantly started to construct a way home.

Also; Garnet already opened the doors in Together Breakfast. She didn't use anything to open the door, only her own gems.