Earthquakes always begin with the creaking joints between the windows. A few noises pop around the room, and it escalates from there.
The next thing to happen is the rattling of windowshades and metal. Filing cabinets and desks join in and clatter together. This is when the room comes alive. This is when the plants dance, the blinds sway, and hangers swing.
After so many years of being no more than an occurance, or at most, an annoyance, earthquakes are able to cause a tension where everyone locks up and confirms that they all feel the shaking. Will this be the one that brings down the building?
Every time, a decision must be made whether or not to err on the side of caution, and to run outside or hide under a desk. Nobody wants to be seen in a panic, only to have the earthquake die down immediatly after. However, nobody wants to die before the earthquake dies down. Actions are taken as a group, and as one person decides to go outside, the rest will follow.