The paper is due at 4 p.m., and you're scheduled to work at 2 p.m. Take your time with your paper and ditch class if you're not finished before work. Call your boss and professor to say you're sick, then rush to finish the paper in time to deliver it to your professor's office. None of the above, because something like this would never happen to you. It's cold outside, and you're in a hurry to get inside.
Someone coming out of the building opens the door.
Hold the door and glare at the person for not getting out of your way fast enough. Hold the door and wait patiently. The guy in front of you has just cashed out his meal card at Hubbell. He's got a zillion bags in his arms, and his bookbag is sliding off his shoulder. Watch him struggle until he just barely has the door open and then hold it for him.