You can't even escape tests when demons are involved. A test for Sam was set up in this little town where it was discovered that Sam was immune to the weirdo virus which makes questions rise. Well I wasn't the only one that didn't pay attention in history but at least he watched Schoolhouse Rock which is something right? Who cares it's not like History is going to help you when you're trying to find a cure to some bizarro virus that turns everyone all crazy.
The whole town disappeared and poor Sarge ended up getting his throat slit because Demon Boy had to make a call. I guess cell phones don't work in hell no matter how many bars you have. I do wonder about the doctor since she stayed behind. Was she perhaps a demon too? This was some test for Sam so it would make sense that a demon would want to keep an eye on him and stay under the radar to avoid getting sent back to Hell.