Your starting point is on a bridge crossing the (now dried) canal. You're somewhat in a hurry - not only because military helicopters may attack you, but mainly because there'll be a blowout in approximately 10 minutes. When 6 minutes are remaining, you'll be given a warning and a timer appears. Furthermore the area has alot of soldiers and snipers about so expect a fair amount of fighting... in other words, there are plenty of good reasons why you should make your way to the Sarcophagus as fast as possible.