Zombie Outbreak

You and your group of survivors found an abandoned facility in far from civilization.
You discover that this facility was a research station for zombies. You found many zombies trapped in a large cage.
You allowed a scientist in your group to complete the study from the scientists that were previously here. Your scientist studied the zombies for many weeks.
At first everything was going great, but as time passed by your scientist became insane with the zombies. He felt as if zombies had feelings and decided to free them all. Of course, he died from the zombies attacking him as soon as he let them out.
That's the least of your worries right now, the infection is spreading and only a few people in your group are armed.
Help defend the facility!

-Plot inspired by the game "Lab of the Dead."