I understand Christians like to interpret Passover from a Christian centric view, but, as every Jewish child learns at the Passover Seder, the unleavened bread is to remind us of the haste in which the Hebrews left Egypt. There was not enough time to let the bread rise so the children of Israel had to bake their bread before if could rise. The story of the plagues and the exodus (and the meaning of all the items on the table) is told every Passover with a rereading of the Hagadah during the Seder, which is a family meal. The events commemorated by Passover took place at least 1,000, and perhaps 1,600 years before Jesus' time.
Why is this night different from all other nights? -- Please refer to your Hagadah, page 4.
Because Jesus Christ, the Messiah, is the fulfillment of all that God was teaching His chosen people through their feasts and holy days. He is the Lamb of God who takes away the sins of the world.