All those years, he kept the pieces of her together. He wasn't there, but…he was.
So, standing there in the museum, when she realised that just because you change one part of someone else's life, it may not change what was already supposed to happen, he kept her pieces together. They threatened to fly apart, but he was right there to make sure they didn't.
So my brain keeps spitting out these short little things. Plus my now week-old love for Doctor Who (just watched all of season five...loved it!), or, more specifically, 11 and Amy, this got puttered out after watching Vincent and The Doctor.
