Basically, your average DH game, hunting heretics, running from daemons, etc.
We had hitched a ride on an Inquisitorial ship travelling to another sector on the trail of this cult we had been tracking down, when a massive riot broke out, caused by a bunch of angry menials wanting better living conditions, like not being used as lubricant for the ship's guns. They ended up breaking a Gellar Field projector-Macguffin-doo-hickey, and we were the closest group of loyalists with a tech-priest capable of fixing it (that would be me). So we hoof it over there, while the Gellar Field on the ship flickers and fades, letting in all sorts of daemons, who proceed to start killing everything in sight. We lost half the party just trying to get to the projector-doo-hickey, and with the fate of not just the party but the entire ship itself, I rolled to repair the damaged machine.
I rolled a 100.
The GM ruled that I completely obliterated the projector in my clumsy attempt to fix it, thus permanently leaving a hole for the daemons to come in and murder us. TPK.