Travis jumped off to the side, colliding with his sister in such a way that it knocked her and him far enough away to avoid the giant boulder as it came crashing down.
"H-Hooooly crap!!" Kat squealed, "This is not what I signed up for!!"
"Just get a grenade out already!!" her brother hissed.
Obediantly, the twin scrambled to open the flap of her pack, knocking the explosives around until she found - ah! That's it!
Grabbing the baseball-sized explosive, she stood to her feet. "HEY! Lizard-head!!"
As the monster's gaping maw turned towards her, she armed the grenade, took aim...and threw it with all her strength.