It had taken him a moment but the young version of himself realized that Lily was now in danger and begged for her to be spared, Voldemort agreed but Snape knew Lily would never allow herself to live on, in exchange for her sons life, so he had gone to Albus and betrayed the Dark Lord; this was where his potions professor became just that and vowed himself to Lily’s son. Harry found it awkward to watch the usual stoic man cry and beg for the woman he loved, but he also respected the man so much more because of it. 