I feel that I should argue that nobody should have a real idea of where Arastoph is hiding. They heard a gunshot, which is so loud it is difficult to trace in the first place, and his voice, which just came from a general location. He could've moved since then. 

So it seems a little odd to me that in the single second he was visible, they were able to see him, think about their action, then both shoot him. In addition, nothing has been said regarding [i]his[/i] actions. Just seems weird to me.

edit: woop, your IC edit ninja'd me. Still, the point stands. :P