Not totally, well to begin with any way.
Most of us here and in the military analytics world would guess the biggest risk is Putin would give the green light for use of nuclear weapons in Ukraine.
If this was to happen it would be unlikely that the first strike would be anywhere else other than Ukraine and would be (ironically) used with de-escalation in mind.
It sounds insane, using nuclear weapons with a view of de-escalating?
Many military analysts seem to agree that the weapons would almost certainly be low yield (known as a TNW - Tactical Nuclear Weapon) which confirms two things:
Putin will sanction use of TNWs and;
If the West didn't de-escalate in Ukraine he may well sanction use of more powerful weapons.
There is no guarantee Putin would authorise use of a TNW over a populated area, he could strike in an area with little to no human population.
The liklihood of a 'first strike' is not likely unless the State of Russia is threatened - which is also unlikely.