This happened to my group as well. You have to get a Titan using his/her highest jump to jump back up over the rail and go back and slam both previous orbs to unlock the door again. Have them jump on the torch stand on the left or right of the large crystal arch, then jump on top of arch and from there jump up and over the railing above. Run all the way back out to the jump puzzle, slam orb, and then slam orb from the slowest room. The good news is, there are no longer adds. Good luck guardian!