Again and again, Mark kept getting stabbed…
Again and again, Mark kept getting fed blood whenever he went berserk…
This cycle kept going until he became aware enough about what was happening to him…
"No! No, don't you da-!"
"Ahh, stop, drinking, her, blood!"
Mark was saying these words to himself. He was becoming aware. Or rather, he was becoming conscious while in his berserk state…
Based on his words that he was yelling at himself, it was obvious that he was trying to stop an instinctive reaction of his. Similar to an addiction, or like when being possessed, Mark was trying to force himself from doing something that he didn't want to do, however, his unconscious reaction didn't listen. At least, not yet, just like every addicted patients…