On my second attempt on any% no up+a I somehow missplaced the last bomb just before g'dorf (you know, after return to the Patra room with the silvers, up up up bomb to the left). Okay, too bad but my new time would still be much better than my first attempt so lets go into that annoying loop to get back... So i went up a few times and bang... a door with a keylock. I assumed the mobs would drop the key but no... no luck...

PS: Thanks JKoper for the beginner guide with the Blue Ring Route