How come they cut the video right at the start of this idiot hand holding a huge spinning mass, I want to see how he gets started. It jumps to him sitting on it, and if that were to grab, and his left knee was squished between the proverbial rock and hard place, ouch. And then to let the concrete slug drop free to a piece of plywood, it freely was rolling with no one other then the camera guy staying clear. but it could take a weird bounce, and end up rolling into another work area or hole to unknown fools in floors below, watching stupid low bidder's with the wrong tool. They make portable drill presses for just this purpose.
It appears to be all new construction. And seeing the HVAC galvanized stuff in the background, about the same hole size, seems a maintenance access between floors was left off the architectural drawings? Or to prevent fire openings, but to not segregate the HVAC inhibits this safety in concrete multistory. Or I have no clue what they are drilling the big hole for.