Thanks - this did help. Once booted to command line ( because X died):
# setpmac mls/equal startx
There were still messages saying can't access to .Xauthority and etc ( I think because they are on mls/low), it proceeded to show traditional X console windows screens - not KDE. Then I started KDE from one of the console windows:
# startkde
and it brought up KDE. However, it is not a full featured KDE. Captions of the windows are still X look & feel ( kind of interesting to see how X UI mutated into KDE). Opening a new window would be prompted with X grid that I need to place on the desktop and click. User runs with mls/equal. All previous KDE settings are not there anymore - perhaps due to access rights issue with config files. Users can't see full KDE default panel. Only root can access full KDE panel. I guess more exploration and tuning required to boot up directly to KDE as per normal.