Distributions of the relative angle between the magnetic field and the filament (θ_Bφ) in High_B (top) and Low_B (bottom), at different snapshots prior to the onset of the SF (τ_sf), corresponding to the S F E = 0.1% stage. The black dashed lines mark the random distribution for the relative orientation of two independent vectors in 3D. The yellow dotted lines mark the average Alfvén Mach number ℳ_A for filament portions at a given θ_Bφ (scale on the right axis).