The whole ‘roof knocking’ thing (a practice in which a small missile is fired at the roof of a building as an advance warning that it will shortly be destroyed in an air strike) was understood [by Hamas] very quickly. Hamas forces are very light, really, and for them – in contrast to the general [Gaza Strip] population, and this is the great tragedy –‘roof knocking’ gave them enough time to go down into some burrow, or to run between the houses and vanish from the area. But for a family with a grandmother who’s sitting in the living room, it’s a bit harder. And that, too, is part of the whole thing. Because of the huge amount of data being received and sent out, and also because of the amount of targets bombarded every day, you would often get a lot of data that says, ‘such-and-such a number of uninvolved civilians were wounded,’ and you don’t really know who are civilians and who aren’t. This is data that comes from the Palestinians’ sources.