In the graveyard in Tarant, there's a secret tunnel that leads to the Bates Mansion. There's apparently nothing in the tunnel except loads of traps, and I've already gotten into the Bates mansion (by killing the saboteurs who were trying to blow up the machines in his factory). So ... what exactly was the purpose of the tunnel? Plan B? Also (unrelated) does your character become more evil if they steal and pick pockets, etc? What happens when a character becomes thoroughly evil? Playing the game earlier with a different character, I got a warning that my character's morals were failing (after butchering a certain wizard). I'm curious.
I forget exactly what quest gives you the key to the tunnel, but it's there so you can sneak into the dressing room where all the servant's uniforms are kept. It might've been part of the Appleby quest, but I don't think so. If I remember correctly, he gives you a servant's outfit. I don't think so. If pickpocketing does make you more evil, the effect is so negligible that I never noticed. It's hard to be evil in this game. Once you've gone far enough along the evil path, the game branches off. You get different quests to lead you to the endgame than you would if you were a good or neutral character.
I used the tunnel to go into Bate's Mansion and steal. You also get a Fate point when you enter the Mansion this way. I do not know why.
You can get the fate point anyway for climbing down the trapdoor at the other end and going back up before you talk to bates. You get the key if you tell appleby you're going to assassinate bates (or take his journal), you could also kill appleby. When you go up into the house, take some clothes from the nearby chests and put them on.