If you do Glassmaker Part 5 without having completed the previous parts, you will be stuck on the final platform with the floating pillar and have no way to exit the level.

[SweetGoat]

Stuck in mission bug report.  Did Glassmarker Part 5 without having completed any of the previous parts.  Located all 5 clues in part 5.  Went into the statue.  Did the correct selections to end up on the final platform with floating pillar that has an image of the Glassmaker's face on it.

 

I was then stuck there on the final platform.  There was nothing to analyze on the floating pillar or anything else to interact with.  Pressing Escape did nothing and did not bring up a menu.  Jumping off the final platform and falling rightfully just warps you back onto the final platform.  There was no way to exit the level.

I ended up needing to Alt + F4 to be able to get out of the mission.  I logged back in and I'm now going back and actually completing the previous 5 parts so that there is a little "fire" effect on them.

 

I imagine most players will have completed the previous 4 parts before doing part 5, but it does seem like a bug that you can end up stuck in the level with no way to exit.  Just being able to exit with a menu on pressing Escape would be fine.