Your feelings are totally valid.
I don't think it's right that your T sur
prised you with this at all.

I think the right thing would have been to ask your permission to have someone with you and to explain to you why they were doing it, so you would understand, and maybe give you a quickie intro at the end of the last session, just so you could shake a hand or say hello and just see this person in advance and know it was coming.

I would be totally upset as well.