Assuming that it's lunch time when the outbreak begins, I would immediately run towards the closet that connects all the science classrooms. My school is a relatively old building with various closets all interconnected by winding hallways. The science closet is a hallway connecting the chemistry, anatomy, physics, and earth science classrooms.
The cavernous closet has a total of 6 doors, one which leads to the roof and nearby fire escape. And one that leads to a small office space. All the doors lock from inside the windowless hallway which prevents any outside entry. Conveniently, the small office has all