As for role analysis, it seems pretty clear to me that if we have either a doctor or a jailkeeper but not both and two roles canceled each other out night one that we almost certainly have no doctor and the jailkeeper and roleblocker targeted each other. And this is assuming, of course, that there's only one roleblocker. If there are two then there may still be a doctor and no jailkeeper.

Now if I'm right and there's a jailkeeper but no doctor, and the jailkeeper and the roleblocker canceled each other out, then they most likely chose not to night kill hoping to convince the jailkeeper they chose correctly night one. But if there is just the one roleblocker, and assuming they're mafia as there tends to often be a mafia roleblocker, the jailkeeper might very well know the identity of the mafia roleblocker right now which is pretty important.