Evolution of v_∥ (top panel) and v_⊥ (bottom panel) in a region around the FR1 during the FR2 eruption (saturated). The purple arrows denote the velocity field. The green lines show the density isocontours. The dashed and solid black lines denote the vertical axis of the flux rope defined by the criterion B_z = 0 at a time of 166.7 min and time shown in the corresponding panels, respectively.