Quote Originally Posted by MFauli View Post
@Y: The only reason no murder was committed is because they failed to. They certainly tried to kill each other.
The test is clearly serious and life threatening, because people can die. But it equally obviously isn't a test about murders and the teams killing each other, because that didn't happen at all. There were multiple first-class mages on hand to presumably ensure it didn't. The test was not "ok, murder each other."

As for whether you could treat people relatively casually when you were just in a life-and-death scenario with them, there's nothing unbelievable about that at all, even in real life, much less an anime.