We have two action sequences to run!
----
TACTICAL SEQUENCE 1- FIRST ASSAULT ON THE SOUTH ARM
General Coll leads his AT-AT unit in a direct assault to smash the western wall of this part of the city.
Standing off a little way, his heavy war machines blow enormous chunks out of the walls trying to create either a breach, or something scaleable.
Closer into the action, AT-ST units roam, angling upwards to pick off the defenders on the upper walls.
Meanwhile it is the stormtroopers units all around that make the direct assault. There is a vicious exchange of fire around the base of the walls as the defenders blast away on those down below. Three times so far the troopers have tried to scale the walls via a path blown away by the AT-ATs. and three times the attack has been repulsed.
Now a change. With the defenders exposed whilst mounting their vigorous defence, a bombardment from the Star Destroyers begins aimed at this sector.
In the ensuing chaos, and now supported by increasing fire from the AT-ATs as Coll brings them closer to the action, the troopers have managed to scale the wall at a single point. The first chance to get into the city proper has been created.
The Imperials immediately order all assault groups to the scaling point. If the damaged section of the wall collapses it will form a breach, but that is not yet known. All that is important for now is whether the Imperials can secure their bridgehead.
All Rebel personalities in the immediate area dash over to repel the Imperial invaders...
---
TACTICAL SEQUENCE 2- REBEL COUNTERSTRIKE TO THE WEST
The artillery units that destroyed the shield generator still remain firing at the city. Lowering to their minimum elevation they are pounding the wall to pieces.
When an orbital bombardment starts to blow away defenders in this sector also, the Imperial assault pauses, not wanting to have its own men destroyed, and waiting for the moment after the bombardment finishes to attack at the moment of maximum shock.
At this point the Rebels launch a daring assault into the heart of the enemy forces. Riding out on Osokan Hunting skiffs, the defenders launch a desperate sally towards the artillery units. Caught off-guard by this surprisingly organised response, the skiffs are through the Imperial front lines in moments and tear towards the artillery. If those artillery units can be disabled, even temporarily, the battle may well swing back in favour of the Rebels.
Two Imperial Commanders involved in the attack on the West Arm are the only ones with the presence of mind to organise a fast enough response to the Rebel incursion. They bring in their men to the defence of the vulnerable artillery.