Yeah but it's Moffat Doctor Who. Lots of people have died and miraculously come back, especially this season. More than Dragonball Z

(Also it could be referring to Clara becoming some sort of Dalek/human hybrid, also as a call back to her first appearance on the show as Dalek Clara, as well as the start of the season being foreshadowing when she hopped inside the dalek…)

It's gotta surely tie into last seasons finale with the hybrid cyber-man/Clara's bf… Surely that's what Davros was referring to and the rest are maybe red herrings?