After a girl throws water on Jade. Jade's face and neck are wet. Then she appears dry. In the next scene in the hallway, Jade is wet again.
The teacher says, "It's World War II, 1944, you're in a submarine, 1,700 feet down in the Atlantic Ocean, and you're probably going to die." That is well beyond the collapse depth of a World War II-era submarine. A submarine from that era would have suffered a hull collapse prior to reaching a depth of 1,000 feet.
Cat claims when she was eating French toast in a restaurant and was laughing and started choking and said the lady who ran the restaurant made Cat leave. If no one saved Cat then she would've started to lose oxygen and would've passed out and the lady who ran the restaurant could lose her job for negligence.
Cat claims to Tori that everyone at Hollywood Arts has to play a musical instrument. But Cat, Trina, Jade and Beck do not play instruments. Although Cat is an airhead to claim this.