It is, and one that I feel is often neglected in RPG's. Not many people are capable of killing another person in cold blood. It is one thing to plan a murder or, as is the case here, violent assault but another entirely to face someone and kill them.
As for the OP:
I dont think that we should consider violence to be the first resort in ME. In the real world violence has never been a common first resort, not for humans and not for any of our animal relatives either. Which suggests that violence as a first resort is literally not in our genes, and also not advantageous.
Even violent thugs used to getting their own way will usually stop short of violent assault as a first resort, often preferring intimidation as a first resort.
More generally speaking there is a sort of rule to how such confrontations go. I know of this rule as an escalation stair, but it might go by other names. The idea is that there are a series of steps (hence the stair metaphor) that a confrontation goes through before it ends in a lethal fight. There might be any number of steps, once a meeting with the potential to escalate happens. Usually it start out with a confrontation with an implied conflict, e.g. we cannot both win this gauntlet, or you want my flag, and I want to keep my flag.
If they play capture the flag like we did in my elementary school then the confrontation happens something like a meeting between members of opposing teams with the "attacking" team trying to bypass the "defending" team. The initial confrontation usually starts with both sides trying to gauge each other. The first escalation is an attempt by the attackers to bypass the defenders, usually by trying to run by them, if that fails the second escalation is an attempt to push the defenders aside in direct physical contact. In school this is pretty much as far as it went. Of course theres nothing to prevent it from escalating to an attempt to push someone over, this time both parties have the potential to escalate, whereas before only the attackers could escalate. The fourth escalation is fisticuffs and the fifth is drawing a (lethal) weapon (assuming that anyone present even has a weapon).
It is important to stress that in real life it is not easy to bypass such an escalation stair, as there is something inside the head of most people that tells them not to. Usually when people skip several steps in the escalation stair we consider them to be unhinged (for good reason).
I try my hardest both as a player and GM to keep the escalation stair in mind as escalating wildly is much easier in an rpg than it would be in real life.
As for how individual people would react, there is considerable variation. Some will be gentlemanly others will be down to business. Some will try to escalate some will be more cautious. Some rare few people might be willing to commit murder over an exam most will not.
Ars magica canon is unlikely to provide you with any definitive answers as the question you pose goes beyond what is ars magica canon and into the underlying assumptions you make about human nature (in your game, but likely also outside it), and what expectations you and your players have for how the game is supposed to go.