Hit the Kerch bridge, eh? While this has some hefty logistics implications, it also seems like a psy-op statement of intent. We're coming for Crimea, and we're not leaving you anywhere to run. So if you come over here...we're going to kill you.
The biggest risk factor right now IMO is this:
A Ukrainian workers’ union representative recounts the deteriorating working and living conditions at Europe's largest nuclear power plant occupied by Russian forces—and how they could lead to a disaster.
thebulletin.org
Given that the Russians have now disconnected the plant from the grid via shelling, I think their reply will be to let the plant go and blame Ukraine for the result. They can't fuel the generators without diesel, and that will lead to an accident in short order.