The lesson is harder than expected for most students

Nick looked around, and a frown appeared on his face. "Is it me, or does it look like everyone is going to be late for teacher Biro's class?" He said after noticing a couple of students in the hall who wasn't even their classmates.

Vincent summoned his watch, and his eyes opened wide. The time taken to teleport was different. Only thirty minutes had passed. They teleported half the time of the previous use.

"Vincent, I something wrong? And... what is that strange object in your hand?" Nick curiously asked.

"This is a special heirloom that tells time. It took one hour to teleport four people, but thirty minutes to teleport two. Doesn't it mean each person takes fifteen minutes each to teleport?" Vincent showed Nick the watch and pointed at the time. 

[Wait a second. Doesn't this mean we are half an hour earlier than expected? Lilith and Clair are going to arrive earlier too.]

-Good thing I checked the time.-