>What is the purpose of 'ambush drive'? To drive someone out of
>the room?

...

Pretty much, yeah.

>Rangers need to be able to specify
>a direction for that drive, without it, drive serves no real
>purpose.

Clearly, we don't agree.

If you like, think of ranger ambush drive as the closest ranger equivalent of assassin's strangle. Neither is, by a long shot, the most effective method for doing what those skills do.

However, both allow you an extra tactical option, one your class wouldn't otherwise have, and some classes lack entirely.

There are certainly good uses for even a random one-room drive; some are gambles at getting the direction you'd actually want, and some aren't. If you can't come up with any of these uses (and from the ideas I've seen in your post, you don't seem to have), just don't use this option and you'll probably be happier.