The Doctor sighed then answered, "Fifty years. I'd set up at a university, started teaching classes there. The vault was hidden in the basement. I needed to keep it protected, so none of your enemies would come to try to finish you off." He took her hand again, gently using his thumb to stroke small circles upon her skin. "You told me you were on my side, but it was hard to tell whether you were lying or not. I wanted to believe you were on my side. I wanted you on my side."
He gazed into her eyes. "I was, which was funny, because I started with the Master before my memories of you appeared. Which is another reason why I believe these memories are true." He lowered his voice, even though there was nobody else near them to listen as he confessed, "I missed you. I wanted you by my side. But the Master and I were always fighting. It was like a competition, who would be on top of the other."