PPL here, so please be gentle.
Isn't one difference between pan and mayday the runway state, as in pan doesn't guarantee a sterile runway and mayday does?
My personal experience only extends to light twins and I realise that these are very different to 757s, but were I on one engine, I would wish for a sterile runway, as I wouldn't fancy a one engined go around and diversion in the event of a runway incident.