Rogue wave events (RWEs), uncertainly emerging localized extreme-amplitude events, ubiquitously occur in various nonlinear wave media. They have been mainly studied in the weakly disordered wave state with a single dominant wavelength scale. In this work, beyond the conventional stability approach, we experimentally investigate the rogue wave formation in the three-dimensional (3D) multiscale dust acoustic wave turbulence from the views of spatiotemporal waveform dynamics and the wave-particle interaction of multiscale modes. By decomposing turbulent waveforms into different-scale modes through multidimensional empirical mode decomposition, we demonstrate that RWE formation is associated with the spatiotemporal synchronization of multiscale wave crests and their envelope peaks. The synchronized 3D particle focusing by preceding distorted waveforms near low-amplitude holes of different modes is the key leading to RWE generation.