Both Trevor and Niki headed for the door just as
WHOOOASH!
The wall with the window disintegrated into dust, revealing open air beyond.
Soldier and soldier body parts spilled out into the yard.
From the other side of the yard, another voice:
"This way!" Gramps yelled. "Hi!"
He appeared with a weapon in his arms the size of a kitchen chair.
Gramps ran for what looked like a vacant space between two parked cars with Trevor and Niki right behind him.
"Adam!" Gramps yelled.
"I'm here," Adam replied, still invisible. "I've been right behind these two."
Gramps commanded the door to open so they could all get inside.
After which, the van rose two hundred feet in the air, then headed south.