The way I eventually did it was, as soon as the checkpoint loads SPRINT to the mouth of the first corridor, if you're quick you can shoot both of the first guys before they even get to their cover. You will certainly get the first enemy. The second rolls into his cover so it might be best to wait until he pops back up before ending his shit.
No further respawns here. Move down that corridor and then at the entrance to the room just go a bit nuts and empty the contents of a magazine,
I got three or four enemies doing this before I needed to take cover buy the side of the door. Watch for the guy who SWAT rolls in from the left and takes cover behind the servers. You can kill him before he does this but if you miss, Ive had quite a bit of success in taking him out via FMJ throught he cover.
My strategy for the rest of the people in this room was just to continually strafe from side to side of the door, pausing to regen whenever it was needed. The occasional grenade over the back of the room also helped because there are 2 guys ducked down behind the desks in the far distance that are hard to make out.
When you eventually go into the door be carefull as approximately 1 in 5 times there is an enemy to the immediate left of the door.
Now for the hard bit.
I have found it's better to be rambo for the first section of this corridor, SPRINT, shoot the first guy, then go prone behind the cover to the left. Your squad should move up to the doors directly behind you at this point. Whilst you're in this cover its best to alternate between standing and prone, don't crouch beause you seem to get shot through the cover when you do this.
Also be carefull not to get too tight to the wall, there is a gap that the enemies can shoot you through on the near side.
Be patient here and wait for a relative gap in the respawns before moving quickly to the next cover which I think was an alcove on the left. regenerate here.
Continuing down the corridor from here is an absolute bitch.
You should be able to see the entrance to another room on the right from where you're now standing. The first priority in this cover is to keep your sights on that door, an enemy often flanks you and its just an instant death. once you have made sure no one is coming from the right the most important enemy to take it is the one on the opposite side of the corridor to you, standing behind 2 vertical pipes. Pop a cap in him. From here I threw 2-3 smoke grenades midway down the corridor at differing distances then sprinted into the side room. The smoke seemed to work pretty well, I didn't get shot at all whilst making my suicide run. There are guys in this second room, but a lot of cover aswell.
Once you're in this room its pretty standard COD veteran gameplay, just be patient and take out the few guys in the room. No more come once they're gone. Stay low, wait until you're back to full health each time before you pop back out of your cover. I found it easier to go to the rear of this room, but it's personal preference really.
The checkpoint is just out of the rooms other door. There are 2 more enemies in cover at the junction of the corridor. Cook a frag and deliver it to them air mail. I checkpointed once I got the the cover they had just vacated. Be patient, and don't smash you're controller up. You'll get there in the end.