I had no faith in Barry being able to overcome Dr. Russo’s infection because, at this point, they had no cure to help anyone. However, Barry’s confidence in Cisco being the next best leader was well-founded, as he and Team Flash come together to save him and Central City.
It seems helpless as first; Dr. Russo now goes by Bloodwork as he rapidly infects Central City with his virus. Camile and Cecile are trapped within a building, Joe is trying to help his officers combat the growing numbers of infected, and Nash is still underground when a group of infected find him. Iris wholeheartedly believes they can help Barry and is willing to do anything to bring her husband back before the Crisis hits.
I thought Barry was long gone, but periodically he gains enough control from Bloodwork to leave messages for the team on how to cure the city. Cisco and Iris hear it loud and clear, and manage to grab Frost and Allegra for help to spread the cure through the particle accelerator before Bloodwork could spread his infection further.
With Central City cured, Barry exercises his control over Bloodwork to lower his defenses and trap him within Star Labs. The desperate situation showed Cisco he can take over from Barry when he inevitably leaves. It’s not something anyone would want to deal with before Crisis hits, but maybe he and Frost will be more confident in their abilities.
There was a tiny bit of hope that Nash had left for Barry. Nash was convinced he could prevent Barry from dying if he found the Monitor. However, after the cure hits the city and he’s saved, Nash believes it’s the Monitor who helped him and pledged his loyalty to him. That will surely only make the Crisis worse, as we immediately head into it as the clock strikes twelve.