Chevy gives some quick equine commands and then attacks and takes a 5ft-step to 65N5E. Jane attacks. Dan moves to 55N10E, provoking an attack, and tries to bull-rush the beetle out of the arena. Chevy and Jane will take the AoO, if Dan pushes the beetle, despite the danger to Dan.
Edit: Dan will be squeezes if the bull rush is successful. I don't think he takes the -4 on the immediate attack (or the str check), but if Chevy or Jane take their AoO (accidentally) on Dan, his AC will be at -4. ...just trying something different to make your DM life interesting.