This is a great movement to use as a warm-up because it activates the nervous system without overly fatiguing the body. It also teaches you to jump with a weight in your hands, as with Olympic-style lifts.
The movement with the legs should be very fast and explosive. Use a powerful hip action.
The arm with the dumbbell should stay close to the body as it rises.
Remember, while you do pull with the arm, it's the movement created by your lower body that gets the dumbbell overhead.
The MacGyver TV show was about a guy who made complicated machines or devices out of ordinary things. For instance, he could take down a helicopter with a fan, a dough-scraper, and some duct tape. Similarly, he could use a light bulb to make a set of lock picks.