Yeah, he was already booking it. This looks like it was an air combat exercise. At the very start of the video (0:07) you see a big round circle and some lines

Yeah, he was already booking it. This looks like it was an air combat exercise. At the very start of the video (0:07) you see a big round circle and some lines that are spread a the top and close together at the bottom. That's the EEGS gunsight, and in the censored portions of the screen is likely the bandit/hostile he was tracking. (Exercise of course.) Either his target slips out of gun range or he switches to a different mode, but regardless it looks like he pursues, rolls 90 degrees and "buries the stick in his lap" (F-16 has a side stick that doesn't move, but whatever. =). I'm told you have to be careful with this, and probably in the F-16 doubly so. (As C.W. Lemonine has said in a few of his videos, the F-16 will try to kill you.) In the top left of the HUD, straight up from the "C" is a decimal number showing the Gs on the aircraft, and it climbs rapidly from 3-4G up to 9G. He loses about 100knots of airspeed (still pretty fast though!) but then you hear that exhale around 0:18 and he starts to slip off the horizontal and enter that dive. His 9G turn probably is what knocked him out, and yeah, breaks Mach 1 briefly as he heads downward. Then as ya said, he pulls another 9G when the system pulls him out of the dive. The "knock it off" calls after are to indicate that they're not fighting anymore. As I understand, that's not slang, that's the actual terminology used. Crazy stuff.