So yeah, main thing is that his behavior doesn't make any sense if he's town. To try to add some content that can at least be discussed, I'll try to analyse what could explain Wunder's behavior and his patterns.
Here are the assumptions:
a) If Wunder does not act, he remains the prime suspect
b) The longer Wunder doesn't act, the more chance we have on turning on each other, on the basis of "Mafia would never be that inactive/apathetic" or "if he was Mafia he would've conceded".
If Wunder remains the prime suspect, it is bad for him. If he's mafia, he loses the game, if he's town he also loses the game, barring a random doc/cop combo that I very much doubt exists. So Wunder is in a situation where he must get the focus off himself, to have a chance to win the game.
Now the problem is, how does he achieve this. He could either try to defend himself and accuse someone else, or he could hope that his inactivity "proves" his innocence, and we start hunting for a new target.
But while the result of both paths is the same (reduced suspicion on Wunder), the way in which they achieve it is vastly different. And unfortunately for Wunder, he has picked the way that only makes sense if you are mafia.
If he becomes active, defend himself and accuses someone else, he's actively trying to win the game as town. Because if he's town, he not only has to clear himself, but also has to correctly identify the mafia in the other three remaining players. Lynching another townie is just as useless as getting lynched yourself as town.
If he however, just remains inactive and hopes that will somehow make us think he's a bored/bad townie, all it does is clear himself, without so much as trying to actually identify the correct mafia, and thus win the game. There is no town-logic that can be applied to make this the better approach.