Fight is broken, how are you supposed to concentrate on killing the Batomys when Selvaria is running around being an ultimate badass?

I found the fight against selvaria later in the game where she can pretty much nail you almost everywhere on the battlefield much harder...

This boss is maybe the hardest fight on the game, so keep trying : D

VC1 is not so hard, the third one is more difficult.

shoot the guns off.

It's a piece of piss. You just need to knock over the wall ruins (tank or lancer) to force the batons to use it's main gun and then expose the cooling radiators for a scout to lob a grenade into. But you do need to take out the machine gun turrets or your scouts will get shot to pieces when they try to climb the tank.

Once you know how it is easy to get an A mission rating. The important thing is to keep people away from selvaria once she shows up, she hurts and is indestructable so avoidance is your only option.

Edit sorry didn't read completely. If the main gun cooling radiators are not all being wiped out with a single grenade hit to each one then there is something glitchy about the game I think. Final radiator for the tank engine to disable the Batomys needs to be taken out by lancers and your tank.