I've noticed it many times, that if you walk over a medikit just nothing happens. Now I think I know why this happens. Thats what I noticed on dnagames.net a few minutes ago: I was at red base, and i saw a Predatorbox rolling off the edge. I walked over it several times, but nothing happened. But then I jumped to the place where the box started rolling, where it spawned, and wonder - i had the predator bonus.