Answer
According the lab partner, event 1 and event 2 occur at the same time.
Work Step by Step
Since you see the light from event 1 and event 2 at the same time, and the light from each event traveled 300 meters, you can conclude that event 1 and event 2 occur at the same time.
The light from event 1 will reach the lab partner earlier than the light from event 2, since event 1 is a distance of 300 meters away, while event 2 is 900 meters away. However, by using this equation: $t = \frac{d}{v}$, the lab partner calculates that the time difference of the light arriving is because of the difference in distance. The lab partner also concludes that event 1 and event 2 occur at the same time.
