Excuse the double post, but I completely forgot about the question concerning Starkiller's confrontation with the Emperor. Well, firstly, it should be said that Starkiller confronts the Emperor after he has reached amazing new stratas of power -- including his control over the Star Destroyer -- and even then, when he witnesses the chamber in the Death Star: "The Emperor was in front of [the Royal Guards, captive Senators, and General Kota], hooded and hunched, but radiating incredible power."
And after he defeats Darth Vader, the Emperor begins to take control of the apprentice's mind: "The Emperor appeared out of the settling smoke, glee on his face. He raised one hand as though to touch the apprentice. The apprentice felt a wave of hypnotic suggestion flow through him. 'Yes! Kill him! He is weak, broken! Kill him and you can take your rightful place at my side!' The apprentice remained frozen, mesmerized by the Emperor's ghastly charisma.
Rahm Kota senses it in the Force and snatches Palpatine's lightsaber from his waist, dismembers the Royal Guard, and launches himself at the Emperor.
"He struck at the Emperor, who stood, apparently unarmed, with one hand still reaching out for the apprentice. But the Emperor was never unarmed. Raising his other hand, he blasted Kota with lightning before the blow ever came close to falling. Sith energy crackled between them and the Jedi Master fell back, caught in the Emperor's deadly grip."
So he owns an accomplished Jedi Master who challenged the Apprentice with one hand and without concentrating. But when Bail Organa yells for the Apprentice to help Kota, he snaps out of the Emperor's trance and hurls a "hail of shattered transparisteel and debris at the Emperor" who backs off of Kota. Palpatine intentionally falls to his knees and gives him the RotJ-speech: "You were destined to destroy me. Strike me down!"
The apprentice doesn't and Kota congratulates him. As Juno Eclipse and her ship come to rescue them, Palpatine attacks Kota saying "Fool! He will never be yours." Starkiller steps between Palpatine and Kota and a whole paragraph is dedicated to how much the Emperor's lightning is owning him with pain.
And he doesn't tank it for minutes. He takes two steps and is right in front of the Emperor, grabs him, and lets the lightning charge into both of them.
When Vader attacks the fleeing Senators, the Apprentice becomes one with the Force and disintegrates the Senators and engulfs Palpatine and Vader in a blast of Force energy that owns the Emperor's observation tower.
Vader and Palpatine both come out unscathed. They survived the Apprentice when he "was more powerful than ever."