I am having a variation of the classic simultaneity experiment (Explained in http://en.wikipedia.org/wiki/Relativity_of_simultaneity#The_train-and-platform_thought_experiment) From the midpoint of a train 2 laser beams are sent to both sides of the train. The beams reach the 2 end-points of the train. Since the train is moving, Observer inside the train (A) sees the beams reaching the 2 end-points as simultaneous & the Observer in the platform (B) sees it as non-simultaneous. Agree. We have a train which is moving at a velocity where Observer B observes a non-simultaneity by 1 second. Instead of a straight beams, let's send 2 very small pulses. Lets have 2 mirrors on both sides of the train which reflects in incoming laser beams. The beams go back to the center where there is a sensor. The sensor is wired to a bomb which explodes if the sensor receives 2 pulses within 1 second. For observer A, both pulses reach the sensor at the same time and the bomb should take off. For observer B, pulses reach back with a delay of 2 seconds (travel back and forth) between them and bomb should not take off. Will the bomb set off or not?