To get a grip means to control one's reactions or emotions, which is what Jason is trying to do by staying calm.
Context: It opened its mouth and screamed, revealing rows of tiny sharp teeth and clawing at jason's muzzle as jason tried to stay calm and in control with his own teeth.
Hypothesis: It opened its mouth and screamed, revealing rows of tiny sharp teeth and clawing at jason's muzzle as jason tried to get a grip with his own teeth.

Given this context, determine if the hypothesis is true (Yes, no, or unknown)?