This is exactly how the attack is described in the WN... People either skimmed it or just don't remember. There was no giant laser. It's described as pencil thin and fired in large groups. There was only one person he deliberately tortured, the rest was just due to bad aim. Dunno why people think he was torturing everyone when he was only there to collect their souls and leave.
Honestly the WN spends more time describing how the spell works than what he's doing with it.