Vladius said:
...the Emperor shows Luke that the rebels are losing and that he can save them by turning,
I disagree....and if that is what he's saying it's not well established. The only thing he plays on is getting luke to strike him down in anger....when does he imply that if he turns he can spare the rebels?
Were you asleep when he mentioned how badly the rebels were losing, "see for yourself," and then told Luke, multiple times, to take his weapon and kill him?