The Right Forearm can only be On Plane when the Right Elbow is On Plane. And, on the Downstroke, that occurs only during the Impact Interval (Release to Follow-Through).
Regarding "coming from the inside," Golf Stroke Geometry mandates that the Clubhead travel Down and Out to its Low Point (1-L-13). In other words, from the 'inside' toward the Plane Line (1-L-10) as directed by the Right Forearm and #3 Pressure Point.