Friendship Quotes in If I Stay

How we cite our quotes: (Chapter.Paragraph)

Quote #10

That's how I know Kim will be okay. (16.12)

Here we see that Mia would be fine dying and leaving Kim to grieve. She knows her best friend is strong enough to make it without her. But Mia never has the same thought regarding Adam. Is Adam weaker than Kim? Or what's the deal?