He didn't hear Yuna come in, too busy wondering what his younger self was doing right now- no doubt searching for him, definitely. He'd likely pretend for awhile that he was fine, but if something happened to his present self, that meant his past self ultimately wasn't far behind. That, and he was passing out. Quickly passing out, which meant he likely wouldn't last more than a few more days, at best.

The healing waves which washed over him were refreshingly cool despite the snow, causing the Doctor to wake up fully, groaning. He recognized that voice, despite only having spoken to her once or twice over the journals. "Yuna?" he asked, holding still to allow her to untie him more easily. "No, I'm fine. Woke up in the morning and felt like a little torture. Perfectly normal."

Okay, so maybe that was a little much, but he obviously wasn't alright.