Gabriel doesn't either, considering the last time someone pointed a gun at him, it ended in bloody, painful death. Luckily, he's also in control of himself to not do anything too stupid.

Of course, this depends on your definition of 'stupid.'

He throws up a teke shield, between the invaders and his companions--not enough to stop a cannon, but enough to hold off at least one wave of bullets... or whatever is in the guns. It's invisible, but who knows what Gallifreyans can sense?