Vale of shadows

It is not the first posting about this subject, but so far the answers does not help me.
I'm in the vale of shadows and have cleared the crypt located on the top right of the map (crypt 5). I can see part of another maze going east (leading to the mummy) but the door is closed. What action/item do I need to go through? Thanks for your help.

sort of a *spoiler* but really a clarification...
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One of the nasty aspects of this crypt. Actually you can just 'move' into it by squeezing through a narrow passage. Hard to describe exactly where it is... somewhere just before the part where you fight Myrtal's sending and after you open the main door to that section.

Lots of people have been stumped by this, looking for levers, keys, etc. But really, all you have to do is get your cursor in the 'right' place and in you go. Once you are there, you will not have a problem with it any more as the hallways will be well marked.