They could also lock the gith relic behind a tadpole locked container aboard the ship. It would allow the PC a chance to get the relic without having to murder SH. I think it would be a suitable temptation.
I see a different approach. Rushing into the helm, you see the MF fighting the cambion. The tadpole strongly desires to help his kind. Attempts to force you to use its power. Roll to resist. If you resist, the cambion notices you, retreats from ship, sword lost. If you fail to resist, illithid power is used, cambion is injured/distracted, MF kills him. Sword is dropped, easily looted. MF again tells you to use the transponder, then switches focus to remaining attackers.
