Cassian and Jyn: Life after Escaping Death

I still don't understand how we survived, everyone that went to fight for plans died... minus I and Cassian. Everyday I relive that day on Scarif, and everyday I don't understand why I was let to live. I was preparing for death to take me, instead a Rebel ship landed near where Cassian and I were hugging till our end was met. Yet, our end wasn't met.