Boyfriend Dungeon

After finishing all eight levels of the Verona College dunj, you'll reach the boss fight with Dr Holmes. After the first stage of the fight (where the green bar at the bottom says 'initialising') is over, you'll reach the second phase and will see a red bar at the bottom of the screen, with a timer on the left. The timer will slowly tick down - you'll have to beat this second phase of the fight before the timer is empty to 'ace' the exam and get this achievement.

Once you've reached this boss fight you can easily retry it if you don't manage to 'ace' the exam, as you can enter the dunj right at the start of the fight (level 9). I found using Sawyer the easiest, as you can use their long-range glaive attack to hit Dr Holmes over the gaps in the platform.