Sorry Deepblue, got a little over the top.
By the way, i think i just had an idea (trust me, it hurt).
The Gargant and Gigas both have subspace weapons, and both are very rare ships.
So the Shivans would have spare parts in front line cargo depots.
Meaning they'd have spare parts for the Subspace weapons.
I have no idea of the size of the Gigas compared to the Icanus, but if both are of similar size, then its possible that if a subspace weapon could be captured intact, then the Icanus might be able to arm it, and fire it on the Gargant.
This will probably only do a little damage, but might by the GTVA time to regroup.