She's surprised when Ten II doesn't want her to dismantle the dimensional cannon and she does make sure the most important components are removed so no one can do something stupid with it. She doesn't learn until he dies that it's because he always wanted her to have the option to go back if the chance came, she never even considered it herself until then.

Depending on how far in the future he dies and whether I'm in a Time Lady Rose mood determines if she then does go back or if she finally takes it apart. But if she does take it down she makes someone hide the plans from her anyway.