And Valeris, being a Vulcan, had the strength to hold them while she did it.
Umm, why would she need to hold anybody?
I mean, she's killing people by firing a phaser at them at stun setting. Surely she would start
by firing a phaser at them at stun setting, making them unable to resist the subsequent sustained head shots.
Reasonable. And it makes more sense, too. Being a Vulcan, she'd shy away from being sadistic.