Cuts through the pressure support vs. radius inside the Hill sphere for the same times as Fig. 6. Of particular interest is the state of the simulation at t = 0 Ω just after the gap formation run. We find the envelope is in a state of latent imbalance due to the low resolution in the gap formation run. From there, the CSD flows push into the envelope until a new equilibrium is found. The inset shows the evolution of the static shock pressure support. The difference in position between the star and the shock positions at t = 0 − 2Ω⁻¹ showcase the slow evolution of the spiral arms between those times. The black star denotes the same position as in Fig. 3.