Top panel: time to return to R₅₀, t_return, (for returning, in yellow points, and wandering MBHs, in orange triangles) and or time to escape the halo, t_esc, (for escaping, in red squares, and escaped MBHs, in purple crosses) as a function of the ratio v_recoil/v_esc. For wandering and escaping MBHs the time shown is just the time from the recoil kick to the end of the simulation, and should be taken as a lower limit to t_return or t_esc. Bottom panel: radius of the first apocentre of the orbit, in units of R₅₀ as a function of v_recoil/v_esc.