Deadlifts seem to be unique in that they can initiate a lightheaded or dizzy feeling. Usually this occurs right after releasing a heavy load. After browsing around a bit on the web it seems this is fairly common although no real concrete reasons were presented. It's likely that the extreme tension, fully body contraction, and abdominal breathing all affect blood pressure and oxygen supply. It's important to remember that this interabdominal pressure it very beneficial when lifting weights. The idea is to create a "virtual" brace around the spine which helps it stabilize against the heavy loads. Still, make sure to develop a pattern that allows you to release each inhalation.
The video shows an event that I have never seen before! It is somewhat humorous but overall very serious. Still, can't help but smirk as the person filming laughs!
Monday Strength/Skill Work: 3 Exercise circuit. OH Squat 5 X 3. Alternate with dead hang chin-ups (grip with palms facing towards you). Alternate with single Turkish Get-up.