Gosh, this has to be... What? The 4th or 5th time I've explained it to you? Forerunners are masters at manipulating gravity. You see this in their architecture and you see it in their creations. The Didact, like all Prometheans, is outfitted with a device called a constraint field. Based on where the distortion effects lead back to, it is presumably located on his wrist.

You never said anything about this to me I believe that was the unneeded armor change/retcons and if all Prometheans had one why didn't they use it on Chief and touch his butt?