Some thoughts on the OP occurred to me based upon what I've been reading on a model/theory called "structural dissociation". In this model, there are "ANP" -- almost normal parts -- and "EP"s, one or more separated-off emotional parts holding the trauma -- in some of us who have this, esp. from childhood trauma (and maybe adult trauma?) There are books and articles on this now, and other related postings on this site.
The ANP, almost normal part -- is our everyday self, usually has grown some since the trauma; the traumatized EP emotional part might be still "living in trauma time" since we weren't able to integrate the trauma, at the time -- and we often deeply keep ourselves from noticing it too, for our ANP to function better. Unfortunately our brains can't perfectly separate the trauma into an EP bubble, so parts of our energy, ability to feel, connect, be present... can be bound up somehow too. These things seem to be a little different in every person with these types of dissociation.
My sense is that if your traumatized EP is able to be active when with your T, parts of you are feeling safer with your T. That is really wonderful! It's totally not something to be ashamed of; your T could actually feel deeply honored by the events you are talking about -- difficult as they may be. How would you feel if a traumatized little kid who had been in a ball in a corner, peeked out at you finally and said something, even a short sentence, after you'd done lots and lots of work at being trustworthy with the child? Gentleness with yourself is totally appropriate.
If an EP wants to run out of a room, that is ok too (as long as you stay safe!) A person's EPs need a lot of consistent safety to peek out of their dissociation balls -- lots of time... It might be a growth thing going on in our brains, with new connections maybe? We can try to nurture those parts as if they are scared kids (that are temporarily separate from "us"), seems to help for me. I think I felt like the whole "inner child" thing was hokey until I started feeling it; not a separate personality for me, but definitely inner blobs of isolated emotions and memories. Work in progress here... Many virtual hugs to you though :hug: (if all your parts would like them!)