Nissim as lookouts. Kobi and I began digging a trench. The top layer of sand was easy to remove. But then, just a few inches down, our shovels struck something hard. Maybe it was a sheet of rock. Maybe sand packed tight over the millennia. But it resisted all our attempts to break through. We had to find a way to get far enough beneath the surface to install the equipment. I called back Oded and Nissim from lookout duty. All four of us attacked the subsoil with every tool in our backpacks that could conceivably help. It took nearly three hours in all. But we finally managed to carve out a trench that seemed as if it might just do the job. It wasn’t as deep or as wide as we'd planned. But we were approaching a point where we would have to give up. We couldn’t risk any more time digging, and still leave time to attach the intercept unit, cover our tracks and make the rendezvous with the helicopter to take us back into Israel. Achihud and Nissim cramped themselves into the hole and got to work, like surgeons in an operating theater, silent except for the faint hum of the intercept equipment. Within a little less than an hour, they’d finished the main part of the work. During our training exercises, we’d factored in a fall-back plan, a way of ensuring we got the unit installed but without additional equipment to extend its battery life. Since we were still behind schedule, I was tempted to stop while we were ahead. But having come this far, and knowing the potential risks of a further mission to refresh the power unit and replace the batteries, I told them to keep going, and also to take the extra few minutes needed to make sure the equipment was functioning. We had to be out of Egypt by first light, and we were now left with more than an hour’s less time than we had reckoned on to make it back to the rendezvous point. There was another problem, too, which I at first sensed more than saw. A bank of fog was closing in. It had come in patches at first, but was getting