I hope you get back to the school. The key card is on the floor in the middle of the gym, and you just need to run it, grab it, and get out before being hit too much by the spitting zombie. Don’t bother trying to kill it - just get the card, get out the gym, use the key card on the locked door and inside the room is the best weapon you will get. After that, no normal zombie will ever cause you any problem again.
I hope you get back to the school. The key card is on the floor in the middle of the gym, and you just need to run it, grab it, and get out before being hit too much by the spitting zombie. Don’t bother trying to kill it - just get the card, get out the gym, use the key card on the locked door and inside the room is the best weapon you will get. After that, no normal zombie will ever cause you any problem again.