When seeing the doctor, both Cody and Dave froze for a second. They thought they might run into people going up the staircase, but the last person they expected to see was the doctor himself. This was the main person they were aiming for, hoping to capture. Shouldn't there have been several guards, or perhaps a big creature protecting him towards the end?
Either way, both of them were too slow to act, as the doctor had immediately gone down to his waist to pull out the hand gun he had on him.
"Cody!" Dave shouted as he closed his eyes and started to fire away. There was no aiming from Dave, and all the training that he had before had gone out the window, as he fired in panic.
The doctor seeing this moved to the side of the door, and was hiding just behind the staircase that would lead them up to the roof.
"Wait!" Cody shouted. "We can shoot him, but we need him alive. We don't know where the others are?"