but Parson might be eager to take control of the city as soon as he can which might not fit capture
We have no ruling officially, but I have a feeling that if you incapacitate someone, capturing them becomes pretty easy. And if every remaining Jetstone unit in the garrison is incapped and captured, that should give GK control of the garrisson and city.
Also, regarding archers on the walls, Tramennis would have been crazy to leave the archers there. Odds are very, very high that they exited with the ground column that exited. It would be crazy for Trammenis to leave them there uselessly to get captured if Slately loses, which he is about to do.
The real question is, since Charlie gambled so heavily to kill Parson this way and had Jetstone over a barrel, in a position to be dictated to, why Charlie allowed Jetstone to send forces against Scarlet insufficient to win.
I suppose it's possible that those Jetstone forces were going to win before Ace kamikazed, but that wasn't the impression I was getting. As I said earlier, why didn't Charlie force Jetstone to use *everything* they had in the area, except maybe Tramennis himself? If you're going to counterattack the garrison and kill Parson, freaking do it all-out. Doing it halfway is just an invitation to lose half your army for nothing, which is more or less what happened.
The most plausible thing I can think of was that the Jetstone fight was going better than it looked in the comic away from the action, and Ace made a rash call in order to kill Sylvia. Who I have been calling scarlet.
I suppppppose there are two other plausible arguments - that Jetstone didn't have to win, just keep the fight going long enough for the city to go inferno, which would have worked if Ace hadn't kamikazed, or else that Jetstone knew Charlie needed them and bargained hard to preserve more of their force. Still, meh. Throwing everything at Sylvia was the best possible option for Jetstone - the heavier the blow, the less people you lose.
Unless, I guess, no set of Jetstone forces had a shot against Sylvia - but with casters on the scene and Wanda out of the loop that seems unlikely, since Trammenis thought Jetstone had a least a possible shot even with Wanda there.