Politics is 99% posturing, 1% action.

Russia isn't ready to be a sea of glass at this point.

They did grossly underestimate the Ukrainian and international response. Now, Putin slightly fears other countries joining in to Defend Ukraine or even an invasion of allied countries to himself. So he's raising the "alarm" (just like the US, they are already ready, so it's like a fake job promotion title) merely to try to make 3rd parties hesitate from participation.