Since I started flying I have dealt with a few incidents, some large, some small.
Like the Purser that Smirnoff spoke to, panic is not an option. We spend lots of time in the simulators and mock ups during training going through what we would do in various situations, that our reactions are almost second nature.
Obviously, emergencies don't happen very often (thank God!!) But, little incidents like someone being ill, drunk or just scared of flying happen more or less daily, and I personally find that that's where my training really comes into its own.