By your line of reasoning, if you made a kinetic shield while people were shooting at you in order to shoot back, THAT would be breaking the laws of magic since you're shielding yourself in order to kill.
That's ridiculous.
You're right, that would be ridiculous if that's what I meant. It's a good thing that it's not. I'm saying specifically to use magic to either directly kill someone, or to incapacitate someone beyond any ability to be aware of their very immediate doom. I'm not talking about restraining yourself to use magic in creating a scenario where you'll have the upper hand, which is precisely what a warden does.
And remember, a warden is usually MUCH more powerful than those warlocks they are sent to take down.
The tactics are simple:
Warden runs after warlock and corners him. He starts by creating a personal long lasting block that is a great deal stronger than anything the warlock can throw at him. Then he likely creates a huge zone barrier to cut off the warlock's escape. Then he draws his sword and advances on the warlock. Warlock tries to throw a fireball ... sizzles on warden's shield. Draws a gun and fires on warden ... which also sizzles on warden's shield. Warlock tries desperately to throw up a block of his own which warden counterspells himself or using the enchantments on his sword. Warden draws back with his sword with nothing but his Weapons skill to aid him, and decapitates the warlock who royally failed his Athletics roll to dodge.
Again, it's a question of free will. The warlock had no chance magically, but could still choose to surrender. He could (and likely did) choose to dodge or parry. He *did* have the ability to defend himself and was very much aware of his own actions and the actions of the warlock. He was simply outclassed by not only a master evoker, but a master swordsman as well. Wardens' swords are not merely ceremonial you know. They are very very good at actually using them.
And there is at least one stated example in the books where an accused warlock is brought to trial. Which likely means that the warlock did knock him unconscious and dragged him before the council instead of dispatching him immediately.
By your definition, any wizard could simply bypass the first law by casually wandering around, putting people to sleep, and slitting their throats. Rinse and repeat. That's hubris of the very highest order, mate.