Everything that Gary had done till this point, was riding on this test. So it was safe to say he had a reason for his hands being a little shaky.
Kai was watching his underclassman carefully, assuming that Gary might intend to switch the tube out or something at some point, but seeing him do nothing was causing sweat to run down his face. Seeing the blonde teenager so nervous only strengthened Sadie’s belief that they had caught their suspect.
Since it needed his blood Gary asked the two White Rose agents if they wanted something for him to prick his finger. When Sadie offered to do it with her claw, the green haired teenager naturally pulled back his hands. It was then that Kai pulled out a small pocket knife that he carried around.