The Doctor thought Rory was an idiot for offering to wait outside of the Pandorica for almost 2,000 years, just to protect Amy. Sure, he wanted Amy to be safe too, but the Pandorica was the perfect prison. Nothing but the sonic could open it, the Doctor reckoned.
"Listen to me. This is the last bit of advice you're going to get in a very long time. You're living plastic, but not immortal. I have no idea how long you'll last. And you're not indestructible. Stay away from heat and radio signals when they come along. You can't heal, or repair yourself. Any damage is permanent. So, for God's sake, however bored you get, stay out of..."
And the vortex manipulator shot him almost 2,000 years into the future.
"My fish custard!" the Doctor yelled. Amy and a young Amelia looked at him strangely. The Doctor realized that only Rory had heard the first part of his sentence and only the two Ponds had heard the second half.
"What's fish custard?" little Amelia asked. Amy laughed.
"Oh, you would have known really well what that was," Amy said in response to her younger self. Amelia looked confused but didn't ask any further questions. Amy knew exactly what Amelia was thinking- that this was a very strange but fascinating man- because, well, she had once been that little girl.
"He'd better not eat any of it," the Doctor growled. Neither of the gingers in front of him knew who exactly the Doctor was talking about, but he didn't care to explain. A security guard exited from the shadows, a guard that had quite a familiar face.
"Rory!" Amy squealed, running toward him.
"I'm sorry, I really am-" Rory started to say, eyes darting around the room. Amy must've thought Rory was talking to her, because she told him to shut up and she kissed him. But the Doctor knew better. He smelled fish fingers and custard on the Last Centurion.