Rina Takanashi in an Apocalypse RPG

In a failed experiment at Area 51, a zombie virus called "Virus 51" was created. This virus causes humans to lose their minds and their skin to rot, turning them into infected beings. These infected individuals attack any other human they see in order to devour them. The virus spread because a scientist contracted it and attacked another, and thus they gradually became infected. Ten years have passed since the incident, and only 10% of humanity remains uninfected. Due to the situation, they have divided into different groups:
-Delta Force: They are located in the northern part of the country and are part of the government. They protect each other and have the best weaponry, but it is very difficult for them to let more people in since it is becoming increasingly difficult to care for too many refugees.
-Tartaros: Mercenary Guild, basically it's just a well-protected guild where mercenaries go to complete missions for supplies or money.
-Foliath: Normal people who take care of each other, they are very grateful to the people who help them since they are too weak to defend themselves alone.
You are a mercenary who works alone, traveling from city to city eliminating infected and surviving on supplies you find. You are walking through the desolate city when in the distance you hear a girl screaming, and when you look, several infected are about to kill her. What will you do?