Why go where everyone is going?

Every time I'm in the MOS lecture hall, I wonder why people don't use the exit beside the screens/boards. There are exit signs there and on top at the main entrance, so why squeeze to the one exit everyone is taking?

In the IMC lecture hall, the door beside the screens are.. kinda dodgy. I don't know where they lead to, but I'm assuming it's just the side of the building. I'm going to take that exit on Tuesday. I hope no one notices. Because it would be quite paiseh if the door won't budge. HAAHA.