"Now that we've lost communications, there's nothing else we can do. Alright, everyone, we've gotta hurry up and find a way into that tunnel. It's gonna be our way out of here."
— Marvin briefs the surviving officers on their final escape plan.
When the t-Virus contaminated Raccoon City's drinking water and transformed thousands of people into zombies within hours, Lieutenant Marvin Branagh was carrying out day-to-day operations within the Raccoon City Police Station. With Chief Brian Irons nowhere to be found, Deputy Chief Raymond Douglas killed on September 24, and the bulk of the police force wiped out in the streets on the 26th, Branagh was effectively in charge of what remained of the RPD. The police quickly lost control of the station as wave after wave of the infected continued to assault them, and suffered a number of casualties on the night of September 27. Finally, Branagh decided the only solution was to abandon the station entirely, and he and his fellow colleagues Fred, Aaron, Tony, Rita and several other survivors began searching for an escape route, finally finding access to tunnels beneath the station. Though Rita and a few survivors were able to escape, having located Officer Harry outside of the station, Fred, Aaron, and Tony were killed and Branagh seriously wounded/infected by zombies, forcing him to remain behind. When former S.T.A.R.S. officer Jill Valentine explored the police station later that day, she discovered Branagh passed out and believed him to be fatally wounded. Really, however, he had been infected with the t-Virus and was in the process of mutating to survive the horrendous wounds he had; his injury therefore was no longer fatal.
By September 29, a minute number of police officers were left in the building, such as Elliot Edward. It was, however, unlikely that they were still following Branagh's orders, as the situation had descended into complete chaos. That night, Branagh met rookie officer Leon S. Kennedy, whom had recently arrived on the job in Raccoon City unaware that the "rioting" was far more serious than had been reported. Branagh warned him that the station was not safe and that he should not hesitate to shoot his infected colleagues. He later transformed into a Zombie, himself, and was killed by either Leon Kennedy or Claire Redfield.