The Doctor stands up, a little wobbly, muttering, "Be mature, I just woke up from a healing trance after a slug tries to take over my body, only to find the Master taunting me about massively sensitive life experiences, and he wants me to be mature?"

To Bee he says, "He's the one ought be mature, you know, he's the old one. Make him be mature, I'm plenty mature."

Deciding he's not as steady on his feet as he'd like, he braces himself. With a hand on the Master's head.