There are some chests that you have to kill a certain number of the red flames statues to get to. Basically, when you kill one of the statues with the red flame it causes one link of the bridge to appear, but when you kill one of the green flamed statues one link of the bridge will vanish.
I usually go through and get all of the green flamed statues to open up the necessary path, then I go through killing all of the red flamed statues (you might have to zone twice and come back to get enough) in order to make the optional bridge appear, while avoiding all of the green flamed statues.
Hope that helps!
He who fights with monsters might take care lest he thereby become a monster. For when you gaze for long into the abyss, the abyss gazes also into you.