Also, Karen's rationale for saving Harold, where she says that someone who knows he's going to die, could prevent it, but goes through with it anyway because it means saving a child, is the sort of person you really want to keep alive.
Harold playing the one song he knows for Ana - which she sings along to - and being suddenly pulled into a kiss. It's the looks on their faces, and the last note Harold gets out before he's distracted...
Ana: I want you too.
"Sometimes, when we lose ourselves in fear and despair, in routine and constancy, in hopelessness and tragedy, we can thank God for Bavarian sugar cookies..."
Even more Heartwarming when you realize in a blink and you'll miss it scene earlier in the movie, You hear her say she was an atheist.