xCRAZYxFACEx

I just had the same problem. I was able to get out, though. You have to command your brothers to use the rampart, then after they fire it, try and aim away and command them to guard a different spot (so they don't keep using the rampart). Once they're clear, make sure you're looking in the same direction the rampart is facing, and spam the 'use' key until it comes off cooldown. If you do it right, you should enter it like normal and be able to leave as normal too. Hope this helps!