the optimal play would be to target StD as Player A and one of the (semi-)confirmed players with B. If that player gets anything other than a protective role, it seems that they would get a killing role since StD would be lying scum. If Player B does get a killing role, they can just kill StD outright.
I target him as A, if he's a doc then whoever I pass the ability to can protect someone, and if he's scum they can just kill him during the night.
Oh... but whichever player you decide to target, you should probably tell me before we go to night, so that I don't isolate that player.
If I'm understanding your role correctly, if you target me as A and (say) BA as B, we'll both be safe and the ability will get passed.Perhaps Glork target me and whoever I'm going to pass StD's ability to?
So, assuming you're telling the truth, if StD is really a doc, then BA gets doc abilities, which he can use on StD, and StD can protect you (or something along those lines), and BA and I are protected as well. If StD is scum, BA gets to kill him.
The problem is that we can't protect you if he's scum. So it might be better to lynch him anyway (then you target me and BA as before, and I send a doc ability to BA, who protects you).