You try if you could manipulate her mind

Sitting in the toilet stall you focus on her brain and her mind. You think for a moment how it works and after a minute you just try to "programm" her a bit. You think:

"Emma, you will always do what I tell you to do. Even if you would have never done it if somebody would have told you this. I'm your master and you're my ****. Even if I'm not in my body you know where/who I am so you can listen to my commands but you will still think I'm that person. You will still act normal and you won't know that it's me commanding you. You will think that the things you do were your decisions. As long as i don't command you to do something (like when i say 'would you...' or 'could you ...') you don't have to do what I say or think (you notice when the thought is intended for you)."

You don't know if it worked so you just leave her body and slide out of the cabin. Right in the moment Tina steps into the room "Emma? You were away so fast, is everything alright?" You directly head towards her and possess her. You ask "Emma?" "Yes" she responds. "I'm in here Tina" "Ok, could you let me in ?" "Just wait a I'll be finish in one minute. I'm peeing." You think this would be the perfect time to test if it has worked. "Emma ... let me in!"