Mohammad used his adopted son Ali as Bait

Tabari VI:142/Ishaq:222 "Thereupon Abu Jahl said, 'I think that we should take one young, strong, well-born man from each clan and give each a sharp sword. They should make for him and strike him with their swords as one man and kill him.'

Gabriel came to the Messenger and said, 'Do not spend this night in the bed in which you usually sleep.' When the first third of the night had gone past, the young men gathered at his door and waited for him to go to sleep so that they could fall upon him. When Muhammad saw what they intended to do, he said to Ali [his adoptive son], 'Lie on my bed and wrap yourself up in my green cloak, the one I use when I go to bed. Nothing unpleasant will befall you from them.'"

Today, I am using some early quotes from both Tabari and Ishaq. The context of this passage was when Muhammad's tribe was fed up of Mohammad's antics.

In this case, Mohammad knew that the men of the Quraish were going to descend upon him, and kill him. What Mohammad did was use his adopted son, Ali (father of the Shiites) as bait for the Quraish to kill.

Why did both Ishaq and Tabari include this story?
Is this the compassion and mercy that Mohammad preaches about, that when he is in trouble, he will give you his cloak to wear, where people would suspect you to be, and for him to run away? (For nice Jinns, he gives animal dung and bones, for his adopted son, he uses as a decoy to evade trouble -- http://muslimhadith.blogspot.com/2008/05/animal-dung-is-food-of-jinns.html)

Or was Mohammad being kind to Ali, in order to allow Ali to wallow in Mohammad's semen-soaked clothes -- http://muslimhadith.blogspot.com/2008/05/mohammad-had-lots-of-semen-on-his.html)

Did both Tabari and Ishaq show this to allow Muslims to see what type of man Mohammad was, by willing to sacrifice his son to evade trouble, or, to show Mohammad's prophetic abilities that "no harm" would come to Ali?