My take on Command.
If told to Run you will start moving at 4x your base move. You may perform any free action that does not keep you from running. You may run in any direction.
If told to Stop you will stop whatever action you have been doing. If you are attacking, you will not be able to swing your sword. If you where walking/running you will not be able to move your legs. If you are singing talking... you get the idea. Stop is an ambiguous command and may generate unexpected results (as always it is up to the DM).
If told to Go. You will move away from the person, taking at least double moves. If you can do something that does not interfere with making double moves you may. Flee would be the same, but you must run.
If you are told to Come. You must move towards the caster using double moves at least. If you are a melee person, this was a dumb thing for the caster to do. You may run, charge, tumble, jump, draw your weapon or anything else that can be done while you are moving towards the caster. A Spring Attack against another foe is not allowed because it would slow you down. You may attempt to Overrun any opponents in the way if you honestly think you can make it past them (again DM discretion).
Remember, this is only a 1st level spell. If you wish to be more specific then you need to use Suggestion. Something like: 'Come stand in front of me and do nothing else.' To me, you just can't do all of that with a one word command.
In the game this week my character was told to 'Go home' from a Mass Suggestion (I assume). That would have been fine... but he has no home.

He is a wandering monk, his monastery was destroyed as back story from the DM. He does not remember where it was (Nor until recently that he is a polymorphed half-dragon). I had to ask her where my home was. lol
Astlin