There are three possible answers,

First, he/she might read exactly what comes out in exam, i mean the area he/she concentrate on, it do happens when someone just read like two topics but eventually the topics comes out in exam compared with a students who read all textbook.

Second, he/she might not know anything in the questions set, so he/she submitted early rather than been asking from his/her collegues which might leads to SUSPENSION.

Three-- He/she might have others activities to do like failing a courses which was done previous year but they fix same time for the exams.
these are mysuggested answer

Here is the screenshot