Have a demo
http://min.us/mQvqGzqGAI think you mostly have it working, just have the events trigger off an "Event Touch".
The random movement left/right is a feature of the "Approach" Movement type, it's in case there's a tree or something in their way, they just move to the side every so often so they don't get stuck.
There's obviously better ways to address this potential issue (path generation for example, or only moving randomly if there's something actually blocking the way), but the dumb 'move randomly 1/6 of the time' is very simple to implement, and uses almost no processing power, so I'm guessing that's why Enterbrain implemented it