Islam critiqued invokes the devil; can the Quran be satanic?

In answer to the video "Muhammad, Psychology and Satan"

Let us see how this favorite of Islam's opponents holds up to scrutiny. 

This noble Book is not the result of some human whim. It was an inspiration to Muhammad 42:52, whose descent is independent of his will and desires 53:3. Allah says of his messenger

69:44-47"if the messenger were to invent any sayings in Our name, We should certainly seize him by his right hand, And We should certainly then cut off the artery of his heart: Nor could any of you withhold him (from Our wrath)".

The prophet wont be able to successfully pass off something false as divinely inspired because by the manner of his sudden death, those around him will understand that the prophecy of preservation came true and that what he was about to utter, or started uttering was false. Should he even misinterpret and lie over the true meaning of what is revealed to him, his heart would be sealed and he would become like the worst rejectors among his nation, blindly wandering on 42:24.

Other verses issue similar warnings against tampering with the Quran to such an extent that it was imprinted in the psyche of the memorizers and all the believers. 

When the malicious critics of Islam try using this divine pledge of protection, something no other scripture has ever had, against the prophet, they do nothing but shoot themselves in the foot. For instance when they connect the symptoms of the prophet's death, years after ingesting a poison, to the statement in 69:45-47 about instantly (not progressively) seizing and puting him to death should he try passing off as revelation something that isnt, then they are still testifying inadvertently to the Quran's authenticity; The prophecy came true and the false prophet, God forgive them for that saying, was put to death and prevented. 

When they quote from the false, discredited and discarded story of the "satanic verses" where the prophet says "I have fabricated things against God and have imputed to Him words which He has not spoken" then they are equally attesting to the preservation of the Quran. The same report states that this supposed "coming back to his senses" was caused by Gabriel, who

"came to the Messenger of God and said, "Muhammad, what have you done? You have recited to the people that which I did not bring to you from God, and you have said that which was not said to you".

Even if we assume in the worst case, just for argument's sake, that the prophet did pass off as revelation something that wasnt, then there is still the inescapable fact that he was under constant watch, immediately reprimanded for his deed, and the false revelation pointed and discarded from the rest.