Typically, around both outlet boxes and recessed lighting cans, the router should plunge cut somewhere on the inside, having checked out first for the wiring being set back far enough so as not to be damaged by router bit. Then move over to inside edge (you'll feel it when you get there) then pull out and jump over the ledge riding the outside edge now and proceed cutting / routing following a counter clockwise direction so any wondering of the router is greatly reduced. This way the clockwise rotation (referenced from face of sheet) of the router bit applies force toward the outside edge instead of away from it causing an oops; oh s--it.