There was no MK last round. Meaning either the mafia did not submit a kill or their target was saved. Falcon has already come out and stated that he used a doc save on AV. AV also was consistent in his statements about investigation and follow up investigation information on jazz. Before jazz's death, AV revealed jazz's role and description and then jazz immediately died afterwards. This proves that AV is a special.
Because of these actions and claims, AV and falcon are intertwined. The only scenario I can see AV being mafia is if him and falcon both are mafia, and decided to hold off on the MK and "fake target" AV.
One tin foil theory I did think of was the medkit. If the medkit was in possession of the mafia, then I could see an epic mafia play where the medkit is used on a teammate to prevent the kill. However, I'm not 100% sure a medkit exists in this game, and it sounds like hand sanitizer only protects someone from getting infected, not MK'd. @Zfetch I know you passed something earlier to falcon. Was it hand sanitizer or a medkit, and did it specify what it prevented?