A tip is to warm up the outer with a hot air gun gently, to soften the plastic first, and lessen the chances of it cracking. It just has to be warm enough that it is uncomfortable to hold, but not so hot is cannot be held in your palm. Just do not heat the connector too much, as it will melt the base. That should make the unit easier to pop open, though you might want to experiment on a few cheap ones first.