Lane takes a step parallel to the yellow line. At the point of contact he is behind it (away from the field). Upon contact, Lane's left foot hits the yellow line. After contact, Lane's right foot lands awkwardly a foot or 18" in front of the yellow line, gives out from under him, and his left foot hits the ground just short of the white area as he lands on his hip/rump fully in the white area.
The "blocker" begins behind the yellow line, and bends down just before impact. As he comes up, Lane's helmet is snapped backward. Just before the action goes behind the red-sleeved man, the blocker raises up and slightly forward the instant before Lane's head snaps back and to the right. BACK and TO THE RIGHT.
The blocker ends up in front of the yellow line. Lane's body travels approximately 4 feet, without planting his foot, at an angle that could only happen with an outside force moving in a forward direction (toward the field). Imagine one of those motion-capture ping-pong balls on Lane's right hip, it would show that he was impacted with force moving toward the field.
Whether or not the blocker was intentionally trying to run into Lane, he does in fact bend his knees and step into him, changing his direction. If the blocker was moving backward, he would not have sent Lane toward the field at that angle and he would not have ended up in front of the yellow line.