Calm, collected, factual. Not spewing out buzz words that grab the occasional channel surfer's attention.
But, you can't expect everyone to react the same way.
People differ from each other, they all handle situation differently.
It's one thing when an ex-Marine has sighted a space craft landing.
It's a complete opposite reaction when it's an old insane woman.
She might be spewing her feelings all over the phone, crying, screaming.
But she was truthful.
What I mean by 'real one' had no matter of heightened individuals who have complicated protocols.
Now onto this call, I would expect every co-worker in Area 51 to have such protocols. So it may be fake. But not because of your answer.
Edit: Now I don't believe that alien life is being stored down there. I believe this is just a base designed to fulfill duties during the cold war. Such as create spy planes.