Retrospective Runaround + Golden Badges
http://dulfy.net/2014/11/04/gw2-lost-badge-silverwastes-achievement-guide/
Dulfy is your friend!!!
and don’t forget to go for diving goggles at end BEFORE YOU OPEN LAST CHEST. as long as you don’t open it, if you die you can back to that last checkpoint at the end
You could also ask a kind mesmer to port you back up to the goggles. Mesmer portal will reach from the goggles spot to the top of the shipwreck above the waypoint underneath.
Good luck!