Similar to the results presented in Fig. 4d, the self-gravitating clumps are growing through radial infall. a, The infall rates are computed as the mass flux through spherical shells and steadily increase with enclosed mass. The rate in the single clump of the LWH (dotted purple line) is more than a factor three greater than the three major clumps in the MMH. The circles mark the infall rate at the clump mass. b, The infall time, the ratio of the mass enclosed and infall rate, is an informative scale that can be used to compare against star-formation timescales. This timescale is constant and approximately 10 kyr within 100Mʘ for all clumps and rises to about 100 kyr for the entire clump, marked by the circles. This rapid infall suggests that sufficient mass will collapse into the supermassive protostar before it reaches main-sequence.