<human>: Give me the gist of the text in a nutshell

This happened about 8 hours ago. I am male, 18, and took my first university exam, (studying Economics) today. Having never taken an exam at the university before, I was more worried about the procedure than the actual exam. Apparently my university is very hot on disqualifying you for any reason they can think of. Anyway, I went to the exam, as usual, you have to put your coats at the front of the room. All good so far. Take phone to chair, put in plastic bag under seat. Haven't been put in front of the firing squad yet. I do exam, and decide that I can do no more with 25 minutes left. The rules are that we can leave the exam as long as it isn't in the first half hour, or last 15 minutes. I check the time; "oh good, I can leave early and get a pint before the bus back to halls". I wasn't the first one to get up, so I knew I wasn't going to be murdered by the invigilators. I stand up, walk to the front, cool as a cucumber. I get to the front and freeze. I FORGOT WHERE I PUT MY COAT. There's a line of personal effects about 2 yards deep across the entire front of the room, with about 300 people sitting behind me watching. I look back and forth, but can't find it anywhere. I hear snickering behind me, and invigilators are "reminding" people to stay quiet. After a while of frantic searching I get a tap on my shoulder. An invigilator tells me that I have to return to my seat, as it has entered the last 15 minutes of the exam, and I am no longer allowed to leave. Cue the walk of shame. About halfway back to my seat the whole room erupts into laughter that even the invigilators can't control. Exam finishes, elusive coat is found once most people have left the room, and I decide to go straight back to halls.
<bot>: tried to leave an exam, couldn't find my coat, got told to go and sit back down and about 300 people laughed at me.