As you have more than one student in your class, it is unlikely that all of them got caught in any of the above worst scenarios or went to the wrong classroom. Thus, you might have made a mistake about the time or place the class is held, even if you are confident that you didn’t make a mistake. So you take out our your syllabus to double-check the time and place of the class. Grimacing, you realize that the room number is 440 rather than 414. You run to room 440 and find the class is still there. Apologizing, you begin your lecture as planned.
Scenario 4: You wonder how this can happen on the first day of the class.