The four of spades video was filmed during an Air Force altitude chamber training exercise. One subject, #14, started showing Hypoxia symptoms. It is a textbook example of Hypoxia and is used widely to convey the dangers of Hypoxia.
Several subjects are inside the testing chamber, and one subject, #14, does not have his oxygen mask on. As the oxygen in the chamber decreases, he passes his TUC, his useful time of consciousness. To test his cognitive ability, he is asked to draw a card, look at it, call out its value, and then show it to the others. When Hypoxia sets in, he keeps saying “Four of Spades” over and over, regardless of the card. When the other subjects ask #14 to put his mask back on, repeatedly, he is unable to understand them. He stares blankly and calls out “Four of Spades.” He continues to do this despite the nervous urging of the others, asking him questions like “What would you do if you were in a plane right now?” Eventually the drill ends when they help put his mask back on.