So last night I killed my first player character as a GM. It was fairly brutal to be honest.
We were in Damned Cities, and the acolytes had gotten themselves arrested by Sanctum Enforcers. A short semi jailbreak later and the acolytes are inbetween an Undertow hit squad a force of Enforcers, and 3 Risen (Skarmen had arrived earlier in the day to try and "get the acolytes freed" read (Kill Khan and retrieve the last two mirror pieces))
The Undertow and Enforcers kill eachother, and the acolytes have to deal with the Risen. The guardsmen of the group who had earlier lost a leg gets lit on fire (one of the Risen rolled 97 on the Mutations table).
He just proceeds to burn for a few rounds until -5 hit points in which the players have dealt with the Risen and finally manage to put him out.
I asked the player if they'd have an issue with mercy killing, as I was willing to offer Cybernetic Ressurection to be completed by the next adventure.
Lessons Learned: Fire is terrifying in Dark Heresy.
Any GMs remember/ are willing to retell the story of their first kill?