She assumes this is not an adventure with her, that much is easy to figure out, but she recognizes the first Doctor. His companions. She sees her Doctor. Confusion is all over her face because she doesn't know what's going on, but he's trying to keep it from it. It must be bad. He must do something bad or something bad happens to him. Likely both.
"Doctor!" Clara exclaims as he starts to shoo her out of the room. She plants herself like a tree against his shooing. "Absolutely not! I will not leave! What is it that you don't want me to see?"