Reach cycle 5.
New colors appear in Pharynx.
Enter Pharynx before given the Expose Glyph.
Game drops to desktop yet music can still be heard.
Game comes up again, then drops out again.
Does that repeatedly until I either force the program to close in task manager or inch my way into the portal to exit the chamber.

Once given the Expose Glyph can enter Pharynx without dropping to desktop.

Hi!

I've had pretty much the same bug, except the game still crashed after being given the Expose glyph.
Turns out it was the antialiasing messing things up in my case so I turned it off and everything's fine so far!
Always try turning on and off every graphic options if you have these kind of crashes, just in case. ;)