Sarah can treat the simulation like a sandbox game and do all sorts of things, but any changes she makes will make the simulation less accurate.
By changes, I don’t mean opening doors, or ruffling Carol’s hair, or getting dressed, etc. Interacting with the environment as though it were real will keep things accurate.
If she made a door vanish of opening it, that might affect what’s on the other side. She could see what she expected to see instead of what’s actually there.
If she opens the door manually, however, what’s on the other side will remain an accurate representation of reality