Although in the game I went with a different turn, here I suggest a much more aggressive approach.
You get 6 ranged dice on Grognack, bringing him down to 5 life with average dice.
In the best case you are going to end the game in the next 2 turns.
Sniper, Sin-Sin's ability and your Gunner with Moto Boots can help you getting to Grognack.
Of course this turn got its risks, Grognack might still have 1 Freeze and 2 Gates which would make an escape way easier.
On the other hand with a Charger, a Smasher and For Glory he could do a lot of damage, even more with Brutal Force. He still has access to all the cards.