['Changed a bit' is a lot of an understatement and he's working on explaining, but this is Ian, the hardest to convince of what is right under his nose, and besides, there's more important information to share.

The Doctor nods at Ian. He remembers when they left him. He hadn't wanted them to go.]

Vicki. She convinced me to allow you and Barbara to leave us on Mechanus. No matter the risk it was to be your choice.

Barbara's not come through with you, has she? I'm sorry Ian, she may not be here at all. This place is called Paradisa and while I'm happy to see you, it's with regret to see you here.