Axel was acutely aware of how easily a person could be lost. Erased from your life as if they were never there, except for the gaping hole in your heart. He'd had it happen to him more times than he could count. Thankfully he had come to realise Vanessa was one of the ones he wanted to keep close.
Maybe because he had lost her too, multiple times. Not to death, but to various forces beyond their control. "I will," He said, with a slight nod. "Life is fragile, people come and go. All you can do is love the ones you have with you now, and remember the ones you've lost."