Re: Reason
TBH, that's what I expected to happen. Russia occupies Donbas to pressure Ukraine into granting those regions local autonomy. They become much like Wales or Scotland. Which I suspect would be the outcome anyway.
Alternatively, Ukraine takes the opportunity to recapture Donbas and Crimea, and more people die. Things like Mariupol are progressing much the same way as sieges always have. Encircle, besiege, call for surrender. If the answer is 'nuts!’, tighten the noose and ask again. Defenders and civilians get squeezed into a smaller area, and more die.
Luckily Mariupol isn't surrounded on account of it being a port. So in theory, a naval blockade could allow humanitarian aid ships in, and civilians out. But at the moment, politicians seemed determined to sacrifice Mariupol because the propaganda value is worth more than Ukrainian lives. But that's been Ukraine's fate for the last few hundred years, being a pawn in other nation's geopolitics.