Using a grinder to face housing ends is usually tricky cause the liner is apt to melt, so take your time and keep dunking it in water.

Here's the tip for dealing with your issue though: just squeeze the brakes together with one hand, then pull the housing out of the adjuster before turning it. Give the housing a bit of a wiggle while holding the adjuster and you should be right. It's the sort of thing that's a hassle cause you don't have three hands, but given how seldom your brakes need adjusting, it works for me as a solution.