I think they would.
Russians hate two things. The idea that they are being threatened with invasion. They see that as existential and have a societal imperative to literally go nuclear on anyone who they think wants a land war.
The other is a think we blow off and don’t understand the depth of. A feeling of inferiority leading to a very low tolerance for direct and massive insult requiring back down. They do have a line, and will indeed shoot at you in the right time and place.
That time and place might not be EXACTLY where our MBA Generals think it is.