Please choose the correct ending to complete the given sentence: Travel: [header] How to ride an elevator [title] Press the " up " or " down " button. [step] When you arrive to the elevator, decide which way you are going and be ready to wait. An elevator's arrival time can be affected by many factors such as elevators' traffic, the amount of floors, rush hours, and available elevators due to unforeseen maintenance or closures.

Ending1: [title] Allow any people to leave before entering. [step] This etiquette is practiced in a lot of public situations such as subways or buses, and elevators are no different. Ending2: Pay attention to both of these and make sure that you arrive at the same time. [substeps] Know that elevators have a built-in directional positive-direction variable which is indicative of which direction the elevator is going from. Ending3: If you enter through one of the elevator's pre-event door locks, then have staff quickly clear this way for you. [substeps] Wait until you have gotten off the elevator before i open the door. Ending4: Ask other people around you about their elevator experience to gain ideas about how the elevator works for them. [title] Note the gear system, holding elevator doors open and closing frequently.

Answer format: ending1/ending2/ending3/ending4