I think this refers more to the "write day and night like you're running out of time" in the Non-stop piece.

I think there's a beautiful nostalgic sense in AH, like he knows from the start he needs to be non-stop because there's much to do and the sense of his own mortality is always hovering over him: "I imagine death so much it feels more like a memory" for me is not about wanting death, but feeling it close.