If you are 100% sure you checked all computers and drank water from all the water coolants ,but yet again you finished the game and still do not have those achievements,well you are in luck ! Exit the game and hit CONTINUE, (i did this the next day just to check if it works,some achievements do this on steam,but u need to refresh them to a certain points ) So basically you hit CONTINUE, you are in front of the big elevator core door and BAM the 2 achievements should pop up ! (At least this is how it worked for me )