Peace in Ukraine? Ukraine attacks Russian Nuclear Bomber Fleet at Engels Base. Ceasefire torpedoed?

Today, Ukraine attacked the Engels Base where Russia keeps some nuclear bombers, and a large number of different missiles, with or without nuclear warheads is unknown.
Russia has evacuated civilians from nearby the Engels Base. It is unknown if any radioactivity was set free.
This Ukrainian attack happens after a partial ceasefire has been agreed on infrastructure and energy. Theoretically, the attack on the Engels Base was allowed under the partial ceasefire. But what will be Russia’s reaction? The Ukrainian Engels Base attack seems to be an escalation, certainly involving foreign intelligence and target data. Russia might use this as argument for a very hefty retaliation campaign.