Magnetotail earthward-propagating fast plasma flows provide important pathways for magnetosphere-ionosphere coupling. This study reexamines a flow-related red-line diffuse-like aurora event previously reported by Liang et al., (2011), utilizing THEMIS and ground-based auroral observations from Poker Flat. We find that time domain structures (TDSs) within the flow bursts efficiently drive electron precipitation below a few keV, aligning with predominantly red-line auroral intensifications in this non-substorm event. The diffuse-like auroras sometimes coexisted with or potentially evolved from discrete forms. We forward model red-line diffuse-like auroras due to TDS-driven precipitation, employing the time-dependent TREx-ATM auroral transport code. The good correlation (0.77) between our modeled and observed red line emissions underscores that TDSs are a primary driver of the red-line diffuse-like auroras, though whistler-mode wave contributions are needed to fully explain the most intense red-line emissions.