Doesn’t matter to a DC warmonger with his bloodlust up looking to accomplish regime change in Moscow or his hinterland neocon stooges. Any attack is justification for Article 5.
Poland could respond with a couple of missiles in the Kaliningrad Oblast hitting fairly non-descript targets - say, a couple of barns. The response should be proportional and immediate.
I am fairly sure that Putin did not intend to drop them in Poland, although you can never tell. If it was an accident, then the Russians will probably just accept the retaliation and that will be that.