An excerpt from this chapter:
Finnick knew the moment it happened, when Mags grabbed his face and kissed him, that he wouldn’t be able to hide his pain over losing her, too. His cup of emotions was already filled to the brim when the Peacekeepers in District 4 pulled him away from Annie.
This is why he needed time alone. He didn’t care if Katniss could see his pain. He was tired of holding it in. She let him be by with his thoughts, and he was more grateful to her than she probably realized.
I’m sorry, Mags. He doesn’t know why it’s necessary to think such things now, knowing that she can’t hear or see him, but he does it anyway. I know you’d probably be mad at me for being so weak at a time like this. But I can’t help it. You were like a mom to me. How can I not cry over you.
Finnick tries to take a deep breath, but it goes in shaky and it goes out as silent sobs. You’d probably smack me over the head if you could right now. Finnick chuckles slightly at his own thoughts. But you can’t, and I’m sorry about that, too. He pauses and wipes his nose. I hope it didn’t hurt, Mags. I know it’s too much to wish for, especially now that it doesn’t matter, but I hope it didn’t hurt. Even if it didn’t, I’m still sorry. You shouldn’t have been here. But I know you would ask me who it should be then if not you. I don’t know. I guess no one.