It took me quite a bit of time – from missing the lamp, to landing on the lamp but overshooting the jump to the other coffins. This is not an easy jump, if you don’t have some kind of stat or potion help.
Once there, jump to the light, then CAREFULLY jump to the right-side coffins. You can jump from coffin to coffin, until you are about even with a lamp hanging from the ceiling and the start of the uneven part of the right side coffins: The coffins on the right side of the hall are relatively straight, until you get about 15 feet up. The key to getting through that gate is not to go through the gate but over the gate. You can check some of the coffins but you won’t get much: a few coins, some bone meal, maybe a torch. I don’t know if that’s a glitch or if that’s a graphics issue on my end. Note: I am on the PC version the Immaculate Armor looks “checkerboarded” to me.
