Suppose there are two observers seperated by distance of 2 light minutes. They have 2 identical clocks, which are synchronized. Suppose one of the observer shoots a missile at 3 PM. The other observer, who is able to see him, will observe that the missile has been shot at 3.02 PM. According to the first observer the missile hits the other observer at 3.04 PM (considering speed of missile to be 0.5c), while according to the observer who is hit by the missile, the missile will hit at 3.06 PM. If both the observers are at rest relative to each other, how do they measure different time for a common event?. Am I missing something out over here?