You start with ambush, target will flee and quaff. Happens every time to me. Even if they don't have a potion, ambush lag is long enough for them to get a sizeable head start on the pahtfinding chase.

You start with murder, or entangle, or a scroll/talisman, they will not flee immediately.

Then, you use low lag moves, ie. serpent strike, (if you can't hold them in place with bearcharge), so that when/if they flee, you have time to chase/ambush (pathfinding = no lag while moving) hopefully.

You'd be surprised how many kills you can get just chasing and using murder too. Forget ambush altogether if you can out melee them.

Again, no idea what proper tactics are at hero, but I'll never start with ambush pre-hero unless they are already hurt and I might one-shot them.

EVERYONE will flee if you ambush first, only the "smart enough" people will flee if you try to use ambush later in the fight .

Other tip:
Don't ambush someone in a snare if you want the next command. Waylay them and you can get the next one in. Such as a bearcharge to get a couple extra rounds since they will flee anwyway.

I play rangers on planet Thera, where tricking your opponent into thinking they have the heads up is how you win.