Use (“V”) to show all the patients status on screen. You will have special triage bandages (add them to your action bar/hot key) which should be applied to Critically injured, then Badly injured, and then injured. Once you started treating a patient do not interupt, just finish treating that patient before moving on to another patient. You should select your next patient before your are finished with the first one, then all you have to do is hit you hot key to start the next one.
HOWEVER, I did find out that there was an exploit to get around it (one of those rare exploits where you would WANT a bit of lag). Basically if you spammed “X” to sit/stand/sit/stand, then if a mob hit you while you were sitting and right as you were standing up, then it would register as a crit, but on the server side you would be standing, thus allowing the ability to proc.