She was right. Usually it wasn't. But being stuck on the TARDIS, one that wasn't his own, one he barely had any control over, was frustrating. He didn't like feeling powerless and longed for the days he could explore the universe more openly. Finding people along the way... And he had become more distant from Seeker too, his companion. It didn't help things, it only made him feel more and more alone. Without that companionship, what was he but a lost wanderer? And without the freedom, what was he? A prisoner, held captive by his own determination and willingness to help others. He did it to himself, and that was that.
"I didn't think we'd be travelling together in another man's TARDIS... Sometimes the universe makes things interesting..." he replied, looking up at her. "There is another Doctor here. Looks like me... married to you. Well not you, his you... Might want to be careful there, he might think you're his wife" he warned calmly. Even somewhat warmly. "It's confused me enough times..."