"Time's up, let's do this! Leerooooooy Jeeeeeeeeeenkins!"
With that cackling battle cry, a now fully-grown Groot came storming out of Stark Tower, Kat atop his shoulder in the same fashion as her dad. She wore an anti-grav backpack, and two huge rifles, each practically bigger than her.
"Stay one-on-one, guys! I got these flartnards!" Kat growled, aiming those massive guns at the swarm, and crying out as Groot ran towards them, Kat firing blaster bolts at them from one rifle, and... sigh... flaming bullets from the other.
This was unbridled rage. The fury of a bullied girl who'd been holding it in for far too long.
One soldier managed to get within arm's reach of them... only for Kat to spin around, and shoot him right in the face.
"Blam." She said, paying tribute to Rocket, "Murdered you."