Based on the analysis of vibronic interactions and nuclear dynamics, we found that the early transition into 3 MC states is driven by ligand motion triggered by the MLCT electronic excitation; this challenges the common photophysical 1D picture with the MLCT surfaces parallel to the one of the ground state. We explicitly showed that the early 3 MC population increase occurs concurrently with nuclear dynamics along ligand modes, such as deformation of the middle pyridine ring and internal ligand bending/wagging, which reduce the 3 MLCT-3 MC energy gap and thus facilitate the electronic transition. We explained that this mechanism does not occur for all trajectories, depending on different states of the 3 MLCT/ 3 MC manifolds and initial conditions, giving rise to the component of the branching with a long-lived 3 MLCT state. As the early sub-ps 3 MLCT quenching by 3 MC is a highly multidimensional process, it is not likely that this channel can be suppressed by blocking the relevant modes, as there are too many of them; a more efficient strategy would be to further increase the ligand field strength to even more destabilise the 3 MC states. We note that in line with this interpretation, in the absence of ligand motion such as the case of the previous QD simulations , the early 3 MC is completely missing.