To revive an enemy who has been knocked out or tranquilized, crouch over their body and hold the triangle button. You'll pat your ally on the back and he'll recover stamina. Look for allies marked with yellow brackets on your map; those are the ones who have been knocked out or tranquilized. Doing so will earn you points.

To help a person stuck with a magazine, shoot the magazine from a distance. If you're too close, you'll get caught too. Shooting the magazine will destroy it and make it no longer a problem.

To boost someone up a ledge, look for a tall wall on a map. Kneel down next to it and you should get a special "triangle" command. Hold down triangle when you see this and you'll put your hands out and say something like "Let's go". The other player then goes over to you and hits triangle to boost up the ledge. To pull someone up a ledge is much the same, except you have to crawl down and lean over the ledge, then hold triangle. Again, the other player must move over and hit triangle to get pulled up. Using this can get you around blockades and help you sneak around behind the enemy, so watch for opportunities to do it.

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