You in a Petri Dish is the second stage in Spring for Sensei.
This stage can be very easy if you have Awakened Bahamut Cat. All you need is him. DON'T spawn anything else as they might trigger Ms. Madonna to attack and release a Wave Attack, damaging your A. Bahamut. Wait until you have enough money to spawn A. Bahamut, release him, and Ms. Madonna won't be able to create Wave Attacks because Bahamut will knock her back. Don't worry about Teacher A., A. Bahamut should be able to finish off the base before he becomes a problem.