Guerilla warfare 101 would indicate that you get out of there and go stir up trouble somewhere else. Then again, there may be some cleric urging them to martyr themselves for the cause.
You're using the old manual.
The current revision of the manual says leave some heavily armed 'martyrs' behind, camped out in schools, mosques, hospitals, etc. so U.S. forces will bomb, shell and shoot them all up. Fire a rocket, or a few mortar rounds from a window, then drop the weapon and run like heck and to another building with another rocket launcher or mortar as many times as you can before an AC-130 catches up to you, times a couple thousand 'martyrs' will be an awful mess. All you see in the street is fleeing civilians, and if you catch on, how do you PROVE the unarmed people that U.S. troops are gunning down were 'bad guys', and not hospital staff? Heck, how do the guys on the ground even know? They can't.
A ruined Iraq in total chaos is a desirable and profitable thing for pretty much everyone in the region, except for Iraq and America.
Any neighbor with a border could slant drill for oil, or even use Iraq's instability as a reason to annex terrirory for a 'security buffer'. Heck, Turkey's been sending troops into Iraq to kill Kurds for many years. Kuwait's been tapping into Iraq's reserves since before the first gulf war. You think Iran, Syria or Jordan wouldn't want some nice bonus oil income?