On "No Fighting In The War Room" now, it's seriously hard, there just isn't enough time. Is there no checkpoints on this level at all?
http://www.nextgenwalkthroughs.com/systems/xbox360/cod4/index.php
CP #1: The corner after the dining area / kitchen ~ > 8 min 15 seconds
CP #2: Going down the stairs ~ > 7 min 45 seconds
CP #3: After the large area of creates and before the painful corridor of doom ~ >6 min 15 seconds
CP #4: Before the slow opening of the doors ~ >3 mins 30 seconds
CP #5: Just before you blow out the wall to the war room ~ > 1 min 15 seconds
45 seconds to clear the hallways and the kitchen is just ridiculous.