This is kinda funny....I just read my SW Insider# 95, p. 64 and they have an article pertaining this fight. Most just technical like how the stage was made and so on, but it also describes Sidious take on the fight. The verdict.....He never set the fight up He believed he was more powerful than the Jedi. He does not set-up them up per say in the sense as in say "they are coming and I will set this trap for them so that Anakin will see this" but that Sidious has trained for this and will be ready if they come get him. SW Insider supports this by writing that "A group of four Jedi has come to interfere with his ambitions, but Palpatine is prepared." This is re-inforced by the fact that we see "From a private anti-chamber adjacent to his main office, Supreme Chancellor Palpatine monitors the state pf his plans for galatic conquest." Also the fact that Palpatine is a little irritated by the Jedi arriving early and though he is perpared to fight the Jedi prosecutors because of his previous conversation with Anakin, they catch him off guard. (Perhaps disappointed Anakin wasn't there also, it doesn't say, but this makes sense too.) It goes on to say he is irritated with the fact that "Master Windu proves to be more troubesome" and now has to fight to survive. Anakin was originally supposed to watch the fight in turmoil. (I think this would have been to unrealistic and that the final cut is much more believable) After Mace defeats him and has him pinned, "Palpatine feigns weakness and pleads for his life" and "Anakin is forced to choose loyalties." So...Sidious sets up a play, but only when he is down and out and Anakin is there. We all know the rest...
This is totally opposite to the novel of ROTS. Mace is deep in Vaapad and litterally controls the "shadow's" everymove in the duel, then really takes over when he senses Anakin's presence in the chambers before the anti-chambers. Sidious is confronted in the chamber of the room and has difficulty for a bit against the 4. This is where Mace senses Sidious' strength and makes the decision to emerse deep into Vaapad and locate the Dark Lord's "shatterpoint". In fact Matthew Stover describes Mace as almost enjoying this duel and doesn't give into fear. This how the other three are caught off guard and Mace realizes that fear is the key to the Dark Side's strength. He will not allow the Dark Lord to gain the upper hand and with the overpowering speed of both the Force and Vaapad, Mace engages him with equal lightning speed. Sidious starts to succomb to fear and Mace senses it and uses it against him. Mace defeats Sidious by severing his lightsaber in half. They proceed to have an intense lightning verses lightsaber fight that drains both. Palpatine loses and Mace finds the Dark Lord's shatterpoint. This blinds him to Sidious's true plan. It's ony when Mace loses his hand, that he realizes Anakin's true intentions to have Palpatine alive. (Padme....WHAT?!?!?!) Then we know the rest. And yes....Mace dies. Both the book and the SW Insider state this. So no, he does not get rescued by someone or uses the Force to cushion his fall or everybody else's zany theories.
So, there are two "Official" Star Wars points of view. Seems like this whole saga is "from a certain point of view". :D