Office Escape

You wanted to leave the city for a vacation but an urgent work at office forced you stay in there for the night. You plan to finish the work at night and leave early next morning but in the morning you realize that you are trapped inside the office. You will be laughed at by your colleagues if they come to find you inside the office. You have to get out of the office before anyone comes and finds you there. You know this office very well but you still not find it easy to explore it, find the useful things, get through the puzzling situations and eventually escape.