Peak flux vs. viewing angle of the HLE of GRB 100906A assuming the same structure derived in O20. Circles, diamonds, and crosses represent the same model at three different redshifts: z = 1.730 (actual redshift of GRB 100906A), z = 0.045 (Advanced LIGO and Virgo range for BNS mergers), and z = 0.5 (ET range for BNS mergers), respectively. The color code denotes the logarithm of the time of the peak in the observer frame. Red continuous and red dashed lines mark the flux limit of THESEUS-SXI integrated in 10³ s and 10² s, respectively. Black dashed line marks the flux limit of eROSITA integrated in 40 s. Verical dotted line marks θ_c.