Question

Does the Rabbi have a straightforward explanation of this central passage in the Haggadah? 
Matzah that we eat—why do we eat it? Because our fathers’ dough did not have time to become leavened before the King of kings, the Holy One, blessed be He, revealed Himself to them and redeemed them.
What moment of revelation is being referred to here? If the intention is the plague of the firstborn, they did not leave until morning. And if what is described here is the departure in the morning, then they were driven out by the Egyptians, as the verse itself says, and not by God.