This felt exactly like it did in the novel.
The exams were supposed to last three days. The first day was designed to let the students acclimate to the vampire-infested terrain.
While surveying the area early on, we noticed a fog. It wasn't particularly dense at first, but it was thick enough to block a significant amount of sunlight. This allowed stronger and more resilient vampires of the ordinary class to venture out and attack us. They were still weakened by the sun, though, which made it possible for us to fend them off and kill them.
But here's the thing.
In the novel, the fog was said to grow denser with each passing day. By the third day, it would become so thick that it would completely block out the sun's rays. That was when the real nightmare began. Vampires could move without restraint, launching relentless attacks. Teams that hadn't managed to earn enough points during the early days would either fail outright or, worse, get wiped out.