Not a bug per se, so I didn't file a bug report.
What happened was I got inside this little area to open some prize crates with my Cryotech Alchemer MK II, and one of the bullets that split on impact reached a gate switch and closed it behind me. I'm trapped and have to leave the dungeon.
http://wiki.spiralknights.com/images/7/7e/Trapped.jpg
I actually laughed pretty hard when it happened.
Yeah, it is pretty amusing, though it's a shame that this causes players to lose their progress in the Clockworks. I think we've known that this little puzzle has potential for disaster to be honest — with multiple players, it's very easy for a mean or oblivious player to trap their comrades, and clearly, it's even possible for a solo player to do this.
I'll send out an e-mail to make sure everyone on the team knows about this. Also, for the record, if anyone runs into instances where they become trapped or are unable to advance, that is definitely grounds for a bug report.