It’s a flashback and one that is debatable if real or simply a hallucination on Pamela given if she were around when it happened she would of jumped in to save him. I could honestly see him counting as mute given in the present and a villain we never hear him give anything but a growl or grunt when actually hurt. I mean we have at least one other who are given one minor quote in a flashback when someone tries to give medical treatment even if not easy to hear and yes that character does count given not only described as such in universe but that is only one scene with even then very hard to make out.