Clearly, with their country invaded, their navy seized or destroyed, and chaos growing, the leader of Ukraine could declare martial law and combined with being commander of the military take any action. Assume you had total power to make all decisions, what would you do?
Fight Russia with everything you got. If so, how?
Capitulate. Realize there is no way to win and turn all of Ukraine over to Russia to spare lives, conceding all Ukraineans are again defeated and subjugated people?
Flee. Find another country as a safe haven and get your family, your friends and you and get out of there?
Stick it out. Just ride the wave however it goes?