Since Murarak's son has already fled Egypt, that plan is already useless. The turning point in the whole thing is obviously the military. They could support Mubarak, support the popular revolution, or take power themselves.
I would not discount the last option. If the military does take control of the nation, that does not automatically mean a military dictatorship. They could form a transitional military government and schedule elections. Whether they would allow the Muslim Brotherhood to participate is another question. The military has been fighting Hamas, MB's armed wing, for decades in Egypt. There is no love lost between the Egyptian military and MB/Hamas.