Stein sadism probably works quite well in "instructor mode", but it was seriously creepy when he started drawing on Maka.
I'm still not clear whether Sid was killed as part of the experiment/test or whether they just took advantage of him being killed due to some other unrelated reason.
I'm also unclear on why Black*Star thought bare-handed combat (without Tsubaki) was a Good Idea... but then we already know he's one of those special idiots