"Or I could leave you out here in the light. Now that I think about it you might need a little sunshine." Salv continues, apparently he realizes the fear of being in one place so long then getting moved, "And then I'll rust you shut so you can't feed on passerbys," Normally Salv wouldn't say any of this, but to freeze his blade, he cut off his sensitive side, literally and metaphorically giving him an Heart of Ice. He would snap out of it once he canceled however.