Now that he gained their trust, it is time to execute his plan. The execution is perfect; the problem is when it comes to the timing of the execution. If the nurse didn't appear, Birugenia can finally kill Kotaro without him knowing it while he is asleep. He also attempted it for the second time now as the doctor, but it is again interrupted thanks to Kotaro waking up. Guess that means that the final strike is in the third one.
The fight scene looks great, but what comes after it is so much better. After BLACK defeated the mutant, it is time for Birugenia to show up and fight Kamen Rider. The fight between the two looks one sided as we learn that he is stronger than BLACK and that he doesn't have any weakness. This only leaves him with one option, to summon his bikes in battle! I just love that he the Battle Hopper and Road Sector ramming Birugenia. It's something I didn't expect a Kamen Rider will do since I find that kind of trick kinda cheap, but hey, he ran out of options he has no choice but to do it! At the end, Birugenia leaves and later learned that Professor Kuromatsu is found dead. This means that the hope of finding Nobuhiko is now lessened.