I assume the accuracy of the average arrow and non-professional soldier might dissuade one to get anywhere near the fire range. Enough will fail to launch properly, slip or be dysfunctional that there's no way you'd want them shot from right behind you.
Eh, plenty of people run into the line of fire even today. People don’t think straight when under a lot of stress.
Also, the only safe place to be in War is far from it; so by definition soldiers need to be trained to ignore a lot of threats to their wellbeing in order to do their job.
