Question

"that was my idea if only it would go faster " what was the idea reffered to by sebeastian

Answer 1

Sebastian was referring to be rescued by a helicopter from the jail, before the guards catch up on him.

Answer 2

Pointing to the approaching helicopter, Sebastian Shultz tells Michael that calling a helicopter for escape form the prison was his idea.

ii) Yes, the idea was a good one. However, the idea failed. The helicopter was a bit slow to arrive and the prison guards and their dogs arrive there. In panic Sebastian takes a step backwards and falls off the roof and dies.
hope it helps