Evolution of the average radial velocity of our five filament systems, as a function of their total cold gas mass budget. The shaded grey area indicates positive radial velocities. For three of our filament systems (namely, #1, #2, #4, and #5), the bulk of the filament is moving upwards at early times due to its interaction with the AGN outflows. The radial velocity of the system typically reverses ∼20–40 Myr after the beginning of the positive radial velocity phase. The filaments then continue building up mass while falling back towards the centre of the clusters for ∼20–100 Myr, before being shredded. The time is re-scaled based on visual inspection such that t = 0 coincides with the last snapshot before the formation sequence of each filament starts. For filaments #1, #2, #4, and #5, this corresponds to when the first clumps are visibly starting to move upwards in the direction of what will later on become the filament. For filament #3, there is no visible upward bulk motion as the filament solely forms out of condensation; thus, t = 0 is defined here as the last snapshot before infalling clumps visibly gather to form the filament.