'Keep him on THIS planet' makes no sense
It is too large a concept for J to be able to handle it, isn't it? Keeping someone on a specific planet?
This not only implies that he can choose WHICH planet he's keeping him on, so K has to specify that it's THIS one, pointing at the ground, but also that his task is not just to keep him from lifting off, getting into the air, flying away, but actually control him EVEN IF HE MANAGES TO TAKE OFF, because technically, he's still' on 'this planet' as long as he's in the atmosphere, right?
So why not just tell him 'keep him on the ground' or 'don't let him lift off' or something like that, because THAT IS WHAT HE OBVIOUSLY MEANT to say?
My theory is that the moviemakers wanted to make everything 'fake-epic' and 'galactic', while at the same time, keeping things mundane and stupid.
I still can't get over that 'Galactic Week' BS, where even the warning is 'Earth will be destroyed in 8 minutes'.
Why is the warning eight minutes instead of, say, two galactic days? (I am not going to do the calculation to know exactly how many days of a 'galactic week' eight Earth minutes are, but all this is such BS anyway)
WHY MENTION GALACTIC WEEK AT ALL IF YOU ARE JUST GOING TO INSTANTLY REVERT TO MINUTES ANYWAY?!
So this is the same kind of BS - J has no ability to do anything if the 'bug' manages to lift off and fly away - he CAN'T effectively keep the 'bug' on 'THIS' planet (why even say 'this planet' instead of 'Earth', if you are going to say something this stupid?)...
He can't do a darn thing if the 'bug' manages to lift off AT ALL, so why not just say keep him from lifting off / taking off / flying / using the spaceship - AND SO ON?
This makes absolutely no sense!