When a space marine company finds itself surrounded and outnumbered by the enemy, with out support and no possible extraction few options remain. Never willing to be found wanting in the emperors service, the marines will often fight to the last, selling their lives so dearly that the enemy are crippled for the efforts. Such an action is never taken light heartedly by the marine in command, and only ever in the direst of situations.
This scenario represents such a desperate act by marine forces when being attacked by ork forces. Whilst that is what the original scenario was created for there is no reason why it couldn’t be played with other armies.