You need search or empathy 60% to notice her movements.
To succeed in the below choices you need:
Athletics 50% to:
Lunge for Gina’s weapon and knock it away before she shoots George.
Persuasion 60% or 45% to:
Call out to Gina to stop, then convince her not to kill George.
Intimidation 60% or 45% to:
Threaten Gina to stop her from killing George.
Leadership 60% or 45% to:
Order Gina not to kill George.