Sekraken Possibly. The point was raised in another thread about just moving out of combat and it was pointed out thst there are lots of referrences to being locked in combat and engaged in combat through the combat rules, so that has to be intended to mean something in the end. I'm currently taking the least offensive road of defaulting back to 8th ed's reforming in combat. Mainly because I want that to be how it gets FaQed out.
But then, is it really so objectionable to be able to withdraw from combat in your turn. You are essentially giving your opponent another chance to charge. In this new era of give ground and fall back in good order, making the combat phase more pushy/ less static, is the ability to withdraw out of base to base in the remaining move phase not just an extention of this. I think the lack of rules like an initiative test to break off, no mention of possible free hits or following up by your opponent being in the rules (things you would expect), makes me think locked/engaged in combat means you must stay in base to base.