From what I understand, the army stationed at Beijing also refused to fire on the demonstrators in 1989. However they obeyed the order to leave the city, not expecting what would happen next. That is, the politburo mobilized into Beijing an undereducated army from a remote area in a different province to do the deed.

The Egyptians have learned it seems. From what I understand the army did not just refused to fire but is also actively being disobedient.