I am starting a game based somewhat off Atomic Robo the Roleplaying Game which is based off Fate Core and in this case it should not really matter.
This will be my first time GMing and first time playing a Fate based game for all involved, so I am trying to come up with some easy to drop in situations to teach some mechanics through "show, don't tell"(I will tell too) and to make sure I have a good grasp of these mechanics.
Main (general) questions: When conceding a conflict how much control over the narration does the conceding party have(as long as it is a clear failure of their goals)? Can, or maybe should, conceding party be pushed into other conflict mechanics if it makes narrative sense?
Below is a concrete situation I have been thinking about which brought up these questions: Say I have some NPCs in a cult which are trying to steal tech from Tesladyne for some nefarious purpose. Well they start invading, and the PCs and ally NPCs want to stop this invasion and probably want to figure out what they are trying to do and why. The PCs are winning and so the final couple of enemies NPCs concede the conflict.
What I want to do as a GM is have them escape. So in this case the PCs get some of what they want(stopping the invasion), the enemy didn't get any of what they wanted. Perhaps clues are left behind so that the PCs can, with some work, figure out who these people are. So far so good, seems like it is in the spirit of a concede.
Say the PCs are not happy with this concede and want the enemy NPCs captured, and this would basically give the PCs everything they wanted in the conflict and that basically defeats the purpose of the concede. I see the situation happening a couple of ways, although not sure if I am totally happy with either:
I say "well this is a concede I get to narrate what happens as long as it is it isn't undermining the victory." Perhaps I narrate smoke bombs or a beam falling down giving the enemy NPCs a chance to escape(should I use a fate point from the reserve to declare details like this for my NPCs?).
Or I could say "OK lets enter a contest and give you all a chance to catch them before they escape." This one feels somewhat better to me, but I also am not sure how I feel about someone who concedes pushed into some other conflict mechanic. If the shoe was on the other foot and the PCs concede, would this make sense and should I do it? I do think it fits into the "make things dramatic" scenario, but the purpose of the concede was to get out of conflict(and not let them be able to take these members in).