Cuz main Owen was afraid they might tell Nux about the pregnancy and all if I'm right... not 100% sure
Looks like the governing body of Owen's home planet had him freeze those two as the price for agreeing to keep his situation (the pregnancy) a secret. It might be illegal for Owen to unfreeze them without their permission.
As far as I remember, original Owen went against his Planet's laws, and they were frozen as part of his punishment (as he was pregnant at that time) and as time went on he wanted to take over one of their bodies and travel back in time to be as young and beautiful, as he was when he left Nux.
But I also want to know when they are released, because now there is nor reason for Owen to travel back anymore.
Can someone explain why handkerchief Owen and dark skin Owen were frozen? And why the main Owen has kept them frozen?
I kinda glazed over that part and it seems to be important?