Hardly surprising really, considering where they're based. Nothing major is going to happen, Putin has not gone nuts, hes just flexing his muscles. He doesnt want his Syria win to be seen as just a blip before westernisation of russias spheres of influence continues, but rather as a full stop. Its vaguely possible for this to turn into a limited shooting war between russia and ukraine, but a wider war would be inconceivable and in no ones interests.
I'd agree with the in no ones interests part but not the inconceivable part - some of the biggest wars of our history were before hand considered inconceivable - its a lesson sadly that people are very quick to forget. Often due to 2 parties being backed into a position they "can't" stand down from despite the costs.