How to get this costume off!!!?

Hello.. my brother has a mascot costume that I decided to try on when nobody was home and now I can't get it off... it's very tight fitting and tight around my head and it's hard to breath.. i am writing this through the two little eyes in the mask.. it's all one piece and where the head is attached to the suit and i pulled the zipper up in the back and when it got to the top the zipper broke and now I am stuck inside this thing! Any ideas? I don't want to be wearing this when they come home! it will be embarring .. im about 5'4 and im a girl so i dont have much muscle.. any help thanks!!