It's a good few minutes before Lapis actually reforms. She doesn't want to be trapped in another mirror too, but she also doesn't want to rush and mess up reforming and end up with a glitchy messed up form. Honestly though, she does seem surprised when she can reform, and just spends the first few seconds looking at her body to make sure, and then her surroundings, and finally, Peridot.

"Peridot?" She's not moving away this time, but she's also not moving closer. "Where am I?" But also, more importantly: "Did you free the other gems?"