The reason the video is so "crappy" is that it was shot with el cheapo (expendable) closed circuit video cameras. Back when 757/767 were first rolling out, they shot it on el cheapo 8mm film, I believe for the same reason.
Reason being, nobody is allowed in that building when the test is underway for safety reasons. Max load on a 767 is in the neighborhood of 500,000 pounds, and the wing is designed to carry all of it once the wheels leave the runway. The ultimate load test ran that 500,000 pounds up to 20g - 10 million pounds of force - before the wing failed, and like I said, it was the web of the wing box itself that failed. Spalled metal was flying through that building with all of that 10 million pounds of force when the wing let go. Pieces punched through cinder block walls like butter. The test engineers figured that putting more expensive cameras in with that was contra-indicated.