The buildings in the Central Academy of Drama are relatively old and magnificent, and are generally not open to tourists outside the school.
Students on campus have to rely on their student ID cards to get in. But if you are lucky, you may be able to sneak in without security, but it is unlikely.
If you want to go in, it is best for students on campus to use their student ID cards.
If you are lucky, you can meet one or two classmates at the door and ask others to take you in, but the general security office may be strict. After all, it is a famous drama school, so it is not so easy to get into the exam.