[quote=@Flamelord]
<Snipped quote by Ploxerdon>

'Obey me' is too vague a command to be ironclad, Servants can resist it if they want. All that happens is that they get a nerf to their abilities if they don't obey. 

A better command would be 'You will not harm your master'. Which would solve the immediate problem, though I doubt it would ensure that Roland bothers saving your butt if you get attacked by another servant.
[/quote]

The problem with that command is that Roland will be able to walk away without any consequences. 
At this moment, the most profitable command for Tatsunoko (and something he would think of tbh) would be to force his servant to kill himself.
Though with Gilgamesh watching, that won't just... happen you know.

Edit: I have found the solution, something that is in character... I will post it once I have finished watching UBW.