"Then he called for Moses and Aaron by night, and said, 'Rise, go out from among my people, both you and the children of Israel. And go, serve the LORD as you have said. Also take your flocks and your herds, as you have said, and be gone; and bless me also.' And the Egyptians urged the people, that they might send them out of the land in haste. For they said, 'We shall all be dead.' So the people took their dough before it was leavened, having their kneading bowls bound up in their clothes on their shoulders" (12:31-34). The Egyptians fear that they will all die if the Israelites are kept any longer, and Pharaoh doesn't need any convincing this time. His will is finally broken, at least for the moment. He commands them to leave and asks that they bless him.
"Now the children of Israel had done according to the word of Moses, and they had asked from the Egyptians articles of silver, articles of gold, and clothing. And the LORD had given the people favor in the sight of the Egyptians, so that they granted them what they requested. Thus they plundered the Egyptians" (12:35,36). This was predicted back in Genesis 15:14, when God spoke to Abram - "And also the nation whom they serve I will judge; afterward they shall come out with great possessions." Though several hundred years had passed, God kept His promise. It would seem the Egyptian people knew that it was wrong for Pharaoh to keep holding the Israelites against the will of the LORD. Thus, the Egyptians gave generously to the Israelites before they departed. In this sense the Israelites "plundered" them.
Moses goes on to describe the caravan that left Egypt. There were about 600,000 men plus women, children, and all their flocks and herds. There were likely two million plus people in all. Apparently some foreigners came along with them, too (i.e., the "mixed multitude" mentioned in Exo. 12:38). They left in such a hurry that they did not have provisions prepared for themselves. Pharaoh had paid such a heavy price to force them to stay and now he finally throws them out of his country in the middle of the night! This was urgent business and could not wait until morning light. As we will see, however, he will change his mind yet again in the near future and attempt to go and bring the Israelites back by force.