Why doesn't G-force knock this pilot out twice?
Your body responds to a lack of oxygen to the brain with physiological responses that can take up to ten seconds to be effective.

...The brain is highly sensitive to cellular hypoxia (lack of oxygen), so rapid impaired function and almost unconsciousness follows (A-LOC), and then ultimately total unconsciousness (G-LOC). To avoid this, your body will reflexively make adjustments in heart output and blood pressure to increase blood flow to the brain (by parasympathetic response–an adrenaline surge), but it takes 6-9 seconds for this reflex to initiate.  By this time, unconsciousness has likely occurred, which obviously means no one is conscious to fly the aircraft.

Raptor 9.0g turn

In addition, the pilot likely made greater effort to avoid a second blackout.


Breathing: Rapid (&lt; 1 sec) exhalation/inspiration cycles every 3 seconds.  This maintains oxygen content and decreases carbon dioxide in blood, while also relieving increased pressure of chest, and allowing the heart to refill with deoxygenated blood from the rest of the body.

Isometric Contraction:  Flexion of skeletal muscles of legs and abdomen.  When muscles contract, the small blood vessels in them constrict, making them smaller with less room for blood.  This step increases pressure in chest and displaces blood away from these contracted muscles into the upper body and brain.



Together, some combination of these measures would prevent a repeat blackout.