Sakura to Tomojo to ball no wana (S01E59)

We all headed to the school after Sakura sensed Clow Reed there. When we arrived we noticed a basketball bouncing all by itself. We chased it into a classroom, but the door slammed shut like a trap! We tried to leave, but when we opened the door to the hallway, it just led to another classroom! I was too slow and got stuck in a classroom all alone. Every door just seemed to lead to a different classroom. I think Sakura started getting scared, so I began singing to let her know I was okay. Eventually, Sakura had the brilliant idea of using the Shadow card to find and save me, just like I knew she would! (Crunchyroll)