A long time ago I wrote a post in the FFG-Forum for the first edition of DarkHeresy(tm), as a response to a request from Antony131073. It was about war encounters, and I thought I could just as well put them down here, too. But I will change the rule references to DH2nd.
The PC come across the wreck of a chimera. One of the tracks is blasted (RPG-Krak or Mine, whatever your rebels have) and the rear suffered some hit from an explosion as well, as it is bend out of shape and the hatch partially open. All the other hatches are closed, the main turret is destroyed.
In fact, the rebels managed to cripple the Chimera but were then unable to enter it. They threw in a frag grenade and left the wreck where it is now. PC who like to investigate could either try to force the rear hatch open with a Strenght(-40) test and a very solid lever (they may find one in the ruins with an Awareness test) or one of them could try to wriggle in (Agility/Acrobatics test). If successful, the characters are welcomed by the mess a dozen guardsmen have been turned into by the frag grenade that exploded inside the chimera (Fear test). If they search the interior successfully, the PC might find a Blackhammer shotgun and ammo in a box secured under one of the benches (under lots of gore) (see IH for the BlackHammer).
Ask for an Awareness test at the beginning of this encounter. (Perhaps +10; harder if heavy fighting is going on in nearby areas, artillery is in use or a thunderstorm is raging above). The PC hear the noise of moving rubble and perhaps some mechanical sounds as something is heading into their direction. They need to quickly decide what to do.
An enemy patrol is coming their way, it consists of a number of armed rebels accompanied by a Sentinel with the sigh-hatches opened-up wide. The patrol was dispatched onto a Search&Destroy mission, looking for Recon-Teams of the enemy while doing some recon themselves. Tests for Stealth are in order if the characters want to hide. If the PC succeeded well on their Awareness test, they will get a substantial bonus since they had enough time to look for good hideouts. If the characters think they can deal with (number of PC+2) rebels and an armed sentinel walker, they can try to engage the enemy. A sniper attack on the Sentinel pilot might succeed, but the Pilot should get an Awareness test himself in order to push the button to have the hatches slam shut.
[Round ´em up!]
While the PC sneak past a small market place they become witness to how citizens are rounded up by the rebels. If the characters avoid the open space of the market place they may see a trail of citizens and/or captured fighters being pushed along by the rebels at gunpoint. Will the characters risk the whole mission (or their own safety on the return) by an attempt to rescue the captured people (which could justify a Fate Point) or will they accept that sacrifices need to be made? In the latter case, the GM should describe a short but audible gun salvo from multiple automatic weapons as the PC leave the area.
[The Fires of War]
The path the PC intended to take leads through a region that was set aflame (by design or as “collateral damage”). The fires are already past their zenith but the area is still incredibly hot, filled with smoke and there are still nests of fires.
The characters need to decide if they want to cross the area or if they will try to get around it (with the possibility of stumbling into an active combat zone or a profound delay to their mission). If the PC try to push through (which might take about an hour) separate checks for the effects of the smoke and for the heat are in order: both result in a level of fatigue if failed, plus and another one for every additional (smoke) or additional two (heat) levels of failure. This is based on the assumption that the PC will need about an hour to pass through. The area was likely set aflame by the equivalent of Hellhound Tanks, firebombs from above or something daemonic. Or a lot of Promethium tanks went BOOM…
If the PC pass an Awareness test(+0; +10/20 if they are from the Guardsman Background) they hear the whistling of incoming ordnance. Ask for a Dodge test so they can get some cover against the shrapnel. Then simply describe them what 30 seconds of shells raining down from the sky actually means. They may be stunned (Toughness test?) or suffer nerve damage (Fear test).
After that, a group of soldiers might charge them through the settling dust or the bombardment might be repeated after a minute.
[Into the Line of Fire]
From afar (at least 100m, and perhaps over a rubble field) the PC get under fire from a machine gun emplacement. Ask for pinning tests. From the emplacement, a mortar opens up fire as well. Will the characters be able to get up and run for it before the mortar finally hits its mark? Even without the mortar, this could become a nice “fighting retreat” and a rush to leave the area before an enemy patrol shows up. The one thing that is important about the encounter is that the characters cannot storm the gun emplacement (it would be suicidal) and get into a situation where it is “retreat or die”.