Glitch with saw and wood block

[TheLauraLee]

In the lead shaft B, when you use the saw to cut through the wood directly behind and blocking the fence door from allowing you into the auxilary shaft, every single time I do this, the saw goes invisible, the wood disappears, and the door won't open. Five second after there's a large boom and the rocks in the shaft appear to be settling, but the door will not open. Also, I don't know if it's related or not, but when attempting to stand directly in front of the door on the fence, it's as though something invisible is blocking your way. You can't stand right in front of it. But yes, at this point, I'm stuck and reduced to trying to saw through a piece of wood that is no longer there, hearing a boom five seconds later, and then nothing. Happens.