The short story A DEEPER DARKNESS in 'MARK OF CALTH'
You reach what you believe to be the rendezvous point with Captain Bolinvar and the other Crimson Consuls. They are nowhere to be seen, however. A horde of genestealers bounding up the corridor towards you. You fire off a blast with your storm bolter to keep them at bay as you activate a bulkhead that seems to still have power. The bulkhead judders closed just in time. Return to the MAP to continue your journey, remembering to subtract 1 blast from your original total of 12. Your search for Captain Bolinvar and the Crimson Consuls will continue elsewhere. If you had no ammunition left at the beginning of this encounter then you already know that you are dead. Return to the Map and try again.