Also some of the PDA's are well hidden. I've been through the game many times and search each area quite thoroughly, but have yet to find them all. I too think people need to listen to and read each PDA's content for the story, but I also think they should be able to access cabinets even if they can't find the relevant PDA. Some people have a lot more trouble with the game and need a little more help. I'm not going to dog them if they access cabinets if they can't find a PDA. Then there's the Nightmare achievements. In that difficulty, people are going to need all the help they can get. Getting the supplies in each cabinet might be the difference in getting the achievement or not.