There were times when Starscream had questions. Most of them revolved around himself, but sometimes they fit the grander scheme of events as well.
Shockwave and Megatron having yet another struggle for supreme control of the Decepticons was a prime moment for those kind of thoughts. When he had been in Vos, plotting to overthrow Tarn and destroy their rivals for all time, Starscream had only seen as far as Vos rising to prominence at last.
Instead, Vos was in ruins, as was Tarn, and he had given fealty to Tarn's champion.
It still rankled.
Yet, Megatron had the same drive and need for power that burned in his own core. It was Megatron that made Starscream feel more secure in his ability to one day lead the other fliers to full ascendance. Shockwave had little use for the tri- and tetra-jets as the Autobots seemed to.
With that firmly in mind, Starscream gave his full attention to undermining Shockwave, yet again, so that Megatron could continue to hold the power on Cybertron. Perhaps, one vorn, neither would be in Starscream's way, but as of now, he preferred the mech that more mirrored who he was.