You need to have 2 people (or a second controller) to do it this way.
Find some adrenaline, and then find a ledge. Have the second person walk off the ledge, then have the first use the adrenaline and pick them up. Have the second person walk off the ledge again and repeat the process until the adrenaline wears off, then maybe one more time, just in case you can get one off the tail end of the adrenaline.
You can do this 3 to 5 times per adrenaline shot if you do it quickly enough and they will all count for the achievement.
EDIT: This still works as of Aug 30, 2014, thanks BRARROW for letting me know.
EDIT: Just did this with my girlfriend, she got 5 revives in one shot, so it is possible t get up to 5 revives with one shot if you do it quick enough.
I found this out on the Hard Rain campaign, a teammate got hit to the dock by the tank, and I used the adrenaline shot to see if it would count, I had him walk off the dock 2 more times, and checked the achievement progress and found out all 3 revives had counted.
EDIT: It has pointed out to me that doing this on Dead Centre Survival mode is a good place to go as there are several adrenaline shots you can use. When doing it here have both of your human players grab adrenaline so when one shot wears off you could just have the other one given to you.
Thanks splicegraph for the tip
EDIT: Some people reported having trouble getting this, and found out that you have to do this by walking off the glass paneled walkways, rather than the stairs. (forget who said that, but it was before the site went down, sorry I can't attribute this tip to whoever said that).
EDIT: This tip is courtesy of DragonYen. Thanks for the tip, apparantly your comment was restored, so I can finally accredit you with the tip you deserve :)
EDIT: It has been pointed out that the AI sometimes will interfere with you reviving the teammates. Simply grab the auto shotgun in the beginning and down one person, rather than reload just grab the same one and it should be fully reloaded for you. You should be able to down them before the fully heal, if not you'll have to do it again. While the second AI is picking that person up, shoot them down. When they are both incapped you will be able to do this without any interferrence.
Added this courtesy of SnelleSjonnie.