You don't try to die.
It just doesn't matter as much if you die as compared to others, because he ignores the enemy laner and farms anyways.
The goal is to waste their time, the jungler's time, and possibly mid or even bot's time chasing you around.
Even if they do get the kill, they're going to have wasted so much time it's not going to be worth to get even a 0/0, let alone a 0/3 or 0/4 for example.
He's a splitpusher who gasses waves to death to burn towers down quick.
But Proxy Singed is utter garbage right now.
Too weak, and not worth proxying.
The only thing worth is the early cheese with DFT, but even that's not that good.
Even his mains are suffering dearly.
He honestly needs buffs.