How would Snape have reacted to Draco insulting Harry's Mother?

Been awhile since I read the books so maybe I'm about to get fact checked like crazy but I can't help but wonder if Snape would have had any discernable reaction at all had he been present while Draco called Harry's mother a mudblood?

I've always thought Snape's Worst Memory sequence was considered his worst based less on the bullying he experienced from the Marauders and more so on his use of the mudblood term for Lily as we later find out that that was the final straw as Lily cut ties with him following that.

I know Snape is entirely committed to his role as a double agent and has to keep up his favoritism toward draco/slytherins and bias towards everyone else, but does anyone else think that had Snape been present during a Draco tantrum the mention of what directly ties to his worst memory may have been something to cause even a slight reaction in Snape?