upgrades and such don't really matter, still really odd. To be honest you don't need morphine i think i used it 3 times in the whole campaign just because i wasn't paying attention to what the guards were doing and got caught but it might be helpful for some places.
One example is level 3 with the guards out in the open before the garden but im sure you can get those guys without getting caught. The only thing i can think of it maybe you picked up a faulty disk but your game would be all sorts of screwed up other than just the morphine not working.
Sorry for dumbing it down it was just a little easier to explain that way i wasn't trying to sound like an ass.