Time evolution of critical heights for TI, ${\overline{h}}_{\mathrm{crit}}$ and ${\stackrel{\sim }{h}}_{\mathrm{crit}}$ (using two different values for n_crit), as well as the center (${\overline{h}}_{\mathrm{center}}$) heights around the five eruptive (left column) and five confined (right column) flares under study. The solid black lines connecting crosses mark the values of ${\overline{h}}_{\mathrm{center}}$. Blue and red lines represent ${\overline{h}}_{\mathrm{crit}}$ when n_crit = 1.5 or n_crit = 0.8, respectively, was used as a threshold for TI, computed from the FPIL-normal planes. Violet and orange lines, respectively, show ${\stackrel{\sim }{h}}_{\mathrm{crit}}$ computed from the FPIL-aligned planes. Vertical bars mark the corresponding uncertainty.