In DC's Legends of Tomorrow Pilot Part 1, Rip says "when I'm from, 2166, you aren't considered heroes. You're Legends." and Stein says, "But doesn't a Legend have to be dead...?"
I was like, C'mon Stein, you're one half of Firestorm, but you're not Immortal... Of course you're dead in 150 years...
In 5x10 "Ship Broken", Sara says that she saw all of them die, Ava asks, "What do you mean? We die in, like, 50 years? Or we die with me wearing this exact same outfit?"
I know this might just be a simple coincidence. But this is the first thing that came to my mind when Ava said that.