Asymmetric measurement of the speed of light

the goal of this game/simulation is to get the timers to record different times when light travels Asymmetrically. (if the timer difference is close to or equal to 0.02 seconds assume the timers display the same time. 0.02 seconds is the most accurate unity is at the moment). After watching Veritasiums video essay titled "Why No One Has Measured The Speed Of Light" where he talks about how it is impossible to test if light moves asymmetrically through space(light moves faster in one direction than the other). That didnt make any sense to me, light could move asymmetrically and we wouldnt know ...