there was an aircraft carrier on it's way to dock in sevastopol. the americans denied it, of course. "routine patrols". but, it was sailing in that direction.
if you consider the ramifications of a nato aircraft carrier docking in sevastopol, you understand why putin actually prevented (or at least postponed) a major war from breaking out.
it's one of those "minor details" that most people will never really be aware of, but was the dominant factor in the action.
so, you ask "what else could they have done?", but you miss the context.