Angus arrived at his dorm without any obstruction. While he is entering the dorm, the other students inside the dorm still wake up and stay in the common room.
Fortunately, Princess Jayna is already resting in her own room. So, Angus could immediately enter the dorm without creating a commotion.
After having a hearty dinner meal by paying some points Angus immediately rests in his own room. During these few months of his stay inside the spring dorm, the others already notice Angus's antisocial behaviour. So, they didn't really pay a mind towards him.
They may not notice if Angus suddenly disappears from his room during the night. Entering inside his room, Angus took off his academy uniform change into his prepared training clothes.
While the other students usually use their evening time to study or rest, Angus always uses this time to train his body silently.