I agree with lolagrace - it sounds like she was trying to give you some control of the situation by letting you know you were not trapped and could leave if needed. My T will often say the same thing. She's reminding me that I'm not stuck in my seat and can get up and move and even leave the room if I need to. I understand how that could feel like rejection from a new T, though.

Perhaps, at the start of your next session, you could tell T that you understand you're able to leave if needed, but that's not the route you want to take. Before things start to go south, ask T if she can help you stay present in the room if you start to dissociate. I know how hard that is, but I've found that if I can lay the groundwork, then T has a better idea of what I need when I get to the point where I can't communicate it as clearly.

When T says that I can leave if I need to, I usually respond with "I know, but I want to stay - help me, please?" She'll help me get grounded enough that I can be present and stay in the room both mentally and physically. It's taken me a long time to get to this point, and I started it with letting T know at the start of a session what I needed from her when I started to check out.