Making a face at the concoction, the Doctor nevertheless pulled it close and lifted the bowl. "They can say whatever they like," he noted. "This isn't going to be pleasant." He couldn't quite help a theatrical shudder at the idea of some of the things he'd seen go into that bowl, but he tossed the contents back as quickly as he possibly could, then dropped his head into his arms while he waited to see if it would stay down. It did, thankfully, though his taste buds weren't likely to forgive him.
"Oh, that was foul," he muttered, face still pressed against his forearms. "Thanks, though. Should help, like you said. Sorry I'm missing a few things. I don't actually stay here. Well, I did, but then I needed to stop in at the TARDIS to see the other me, and I never quite left. Not until all of this fuss with the Seal and alternate dimensions." He turned his head so he could see Koschei, and for a few long moments, just watched him, thinking. It was hard to imagine the other Time Lord as the Master. He was so mild-mannered, so inherently kind. Had Rassilon and the drums really had such a profound effect on him? Just one more sin to add to the list of many, the Doctor thought. If it hadn't been for the war, Koschei might never have heard those drums.
"There was a war in my universe," he finally said, not entirely sure why. Perhaps this was some sort of confession. Perhaps, given this chance to sit down with a version of the Master who would listen, the Doctor hoped to finally have the chance to say he was sorry and be heard. "A Time War. You and me--well, the other you--were the only ones left, except I didn't even know he'd survived until I practically tripped over him at the end of the universe. Sometimes, I wonder if he'd have been better off had I left him alone. He was human. Didn't remember a thing about me, or home, or any of it. He could have lived out a human life and never had to come back to everything that went wrong."