Rear wheel cylinder blew out on the way to work today

Clean it all up with a little brake clean, put a little fluid in reservoir, then you can have someone gently push the peddle while you look. Use a flashlight and keep your eyes protected. Even though the line went out you may find that the cylinder is also leaking, so you can change it while you have it apart. Might as well do the master while you're at it, if you suspect it is leaking by.