Beast Wars-Machines Question!

I don't understand what happened after the Beast Wars. It starts off with Primal chasing Megatron through a time gate that sends them to the 50 million years of when the actual Prime and Megatron are in stasis lock. After the Beast Wars are over, Megatron is tied to the shuttle and the Maximals head to Cybertron.
-Why is it that after Megatron gets loose off the shuttle, the Maximals arrive to Cybertron, only to have Vehicons attack the ship and rid of their transmetal forms?
-How did Megatron have enough time to create vehicon drones to attack the ship? Is it because when he got loose, he was sent to Cybertron BEFORE they could arrive, giving him time to conquer Cybertron?
Any clarification is appreciated
-Why is it that after Megatron gets loose off the shuttle, the Maximals arrive to Cybertron, only to have Vehicons attack the ship and rid of their transmetal forms?
-How did Megatron have enough time to create vehicon drones to attack the ship? Is it because when he got loose, he was sent to Cybertron BEFORE they could arrive, giving him time to conquer Cybertron?
Any clarification is appreciated
