Updated 20100507-16:00:
Okay. So, here’s what actually happened on Thursday:

Someone was eavesdropping on a passenger’s phone conversation.  Despite the fact that the entire conversation was in Swahili, the eavesdropper thought he heard the word, “bomb.”  He then panicked and told the bus driver.  The bus driver panicked, slammed on his brakes (in the middle of the road), jumped off the bus (leaving everyone else to fend for themselves), quickly ripped some panels off the side, disabled the engine, and then proceeded to run away screaming, “GET AWAY! GET AWAY!!”  Witnesses to this decided it was an excellent time to panic as well, and proceeded to run in every direction, calling 9-1-1 on any phone they could get their hands on.  Once it hit dispatch, all the cops panicked.  They stuffed their arms full of weapons, and then drove as fast and dangerously as possible to the scene (only about a half-mile away).  On-site, they quickly realized there was no time to ask questions, so they set up a barricade of a good half-dozen blocks, emptied nearly two-dozen buildings, and ordered everyone to stay on the bus.  While all of this was going on, passengers on the bus were talking with family, friends, and police, and were continually assuring people that everyone on the bus was completely calm – albeit quite confused – and if anything, they were becoming more and more terrified by the response of the police alone.

SWAT Team Aiming at Suspect by 100 Club