Just to put it into perspective:

Lets assume half of those 1.1 M find shelter in Gaza but outside Gaza city, (I think this is generous, as it will mean ~2 people living there usually for each person seeking shelter, as 2 M people live in the entire Gaza region). This leaves 550 k people to exit through the three border crossings. This leaves each person an average time of less than half a second per parallel processing capacity of the crossings to cross the border. Note that all three of these crossings are closed if I'm not mistaken.