It really sort-of pisses me off when people say the Jedi got lax or complacent because, honestly, it's not true. The Jedi are way ahead of everyone else on figuring out what's going on most of the time. They're actively investigating things, they're sending people out on secret missions, and they're ultimately the ones who do something to try to get Palpatine out of power even BEFORE they figure out he's a Sith. They're still teaching their children that it is their job to hold leaders accountable, all the way through the clone wars. The Jedi are the only ones who figure out the Sith are out there doing things and look into that. The Jedi are the ones who discover the Sith plot EARLY by going out to investigate an assassination attempt gone wrong. The Jedi figure out that the Sith were behind the clones' creation as a trap for them. The Jedi choose to commit treason by going to arrest Palpatine explicitly because he's become so immensely corrupt and powerful that nothing else will take him down and stop the war.
The Jedi AREN'T lax or complacent at truly any point throughout the Prequel Trilogy. They're being played by Palpatine, sure, and he does very well at it, but they still nearly manage to beat him at his own game. If Anakin hadn't been a complete and utter selfish turd, they'd have won. Palpatine has to work SO HARD to stay ahead of them, he literally knows he has to plan a galactic civil war just to distract them long enough for him to gain enough power to even give him a chance at overpowering them.
The only other person in the films who comes anywhere NEAR the Jedi's level is Bail Organa and that's only in ROTS. Nobody else is truly as aware of what's going on and on Palpatine's tail as the Jedi are. Nobody.
So fuck this complacency bullshit, the Jedi aren't complacent.
Anakin may not have considered it "with the intention of falling" but I think you could make a solid argument that Anakin went to that office fully prepared to join Palpatine, whatever that meant. He didn't necessarily WANT to kill Mace or the other Jedi, but he WAS committed to joining Palpatine. He's trying to convince Mace to stand down and let Palpatine live so that Anakin can join Palpatine and get what he wants from him. Anakin has convinced himself that he may be able to sort-of have his cake and eat it, too. That he can join the Sith and still be a Jedi.
But he's fully prepared to join Palpatine, that's the entire point. He just has to keep Mace from killing him first once he arrives. And I'm sure Anakin was aware that the Jedi WOULD be trying to kill Palpatine because he wouldn't have felt the need to run there and intervene otherwise. If he genuinely believed that they'd just overpower him and imprison him, he'd have had ample time and options if he just waited. But he KNEW the Jedi would be trying to kill Palpatine, so he runs to that office in order to spare Palpatine's life so he still has the option of joining him. Anakin wants to learn Sith powers, but not necessarily be considered a Sith. Because Sith are evil and Jedi are heroes. Anakin wants to be a heroic Jedi but with Sith powers. He's just refusing to acknowledge that those things are mutually exclusive. You don't get to use Sith powers without becoming a Sith yourself. A true Jedi would refuse Sith powers, no matter the circumstances.
So I think Anakin is hoping he can "not fall" when he goes to that office, but he's prepared to do whatever he has to do in order to keep Palpatine alive and get Palpatine's information to save Padme. He's prepared to take down the Jedi if he has to. He's prepared to become a Sith apprentice if he has to. He doesn't decide that in that office, he's deciding it in the scene beforehand where we see him staring out a window in the Council chambers. But he's made his choice by the time he shows up in Palpatine's office.
