Whoever designed the exam is either malicious or stupid.
Who in their right mind kills off trained magic users!? We already heard from Frieren that there is a decline of magic users, and that magic users are hard to train that takes resources and time. The first thought that comes to mind to these examiners is, "Hey! Let's waste time and resources by killing off great potential."
The only reason to do that is if the examiners are stupid, or they've been infiltrated by some malicious force that wants the decline of magic users.