Histogram of the average escape fraction as a function of the time since the last major merger and the gas scale height for galaxies with H >  10²¹ cm (loc-mode; upper panel) and H <  10²¹ cm (ext-mode; lower panel). The dashed and dotted lines refer respectively to the one- and two-sigma distribution of galaxy counts of the respective samples, while the green line corresponds to the average gas scale height of all galaxies in a given t_merger bin.