Case when a BH is let go from R = 1.5kpc in a (dynamically) warm stellar disc (Table 1). In panel (a), the run of L_z is shown as a black solid curve, and radial and azimuthal velocity components are shown in red. In panel (b), the cylindrical radius R and the amplitude of v_• are displayed, each with their own colour-coded vertical axis. In the early stage, dynamical friction makes the orbit shrink; however, the perturber BH acquires angular momentum throughout (panel [a], black curve). Both R and v_• increase systematically from t ≈ 500 Myr onward. The dotted line at the bottom is the z-coordinate bound to ±15pc. Compare with the test case displayed on Fig. C.2.