Complex sentence: Meanwhile, Monarch and Dr. Girlfriend have snuck into the Venture Compound to find a working bathroom, and after that mission is successful, now need something to do, preferably one that would strike at the heart of their archenemy.
Split into simpler sentences: Meanwhile, Monarch and Dr. Girlfriend have snuck into the Venture Compound to find a working bathroom. After that mission is successful the duo now need something to do, preferably something that would strike at the heart of their archenemy.