This undercut is necessary to avoid interference with the teeth from the other gear during rotation. Note that the yellow rack tooth is deep into the undercut space. Figure 1.2.1: The green gear is a ...
Make sure your squat rack has safety features like the spotter's arms. You also want it to have the option to adjust the height of the rack for multiple users of different heights.
While there's been no confirmation of a Metal Gear Solid 6 on the horizon, it seems unlikely that Japanese entertainment giant Konami would abandon one of its most beloved properties so easily.