it is host-confirmed that doctor is a possible role.
beyond that, eevee has explained the present framework. you dont need them to explain how every possible role works in said framework. its easy enough to just apply it.
because in each possible world theres nothing to change.
in one world you are alive and mafia and the other is dead. in the other world the other person is alive and mafia and you are dead. in either world, attempting to kill the dead body changes nothing.
the reason for this is, without any other sources of death, it needs to be wholly ruled out that the player in question is a part of the mafia. for this to happen, all worlds where that player is a part of the mafia team need to collapse. there are 4 mafia in every world. therefore, if 4 people (including the player themself) refrained from targeting the player in question with the mafia factional kill, a world exists where that player is in a mafia team with the other 3 people, and as such they would not be 100% dead
Basically any role in the 2x5 in the OP has a chance of existing. We don’t know exactly which of those setups is this setup, so we don’t know that we have exactly a doctor, for example. But we currently do know that it can exist. Depending on how the game progresses, we will learn that there is either a 0% or 100% chance that a doctor exists by later on.
Does that make any sense lol
I meant if we fast forward to a point where the setup in question is confirmed, then we know for certain whether we really do have a doctor or not, but for now we just know that we might. Think of it as a closed setup in that aspect.