That isn't the route. In such a large organization, even a very very good and proper one, such issues are not to be accelerated to the CEO. If you have thousands, tens of thousands of employees, then complaints like this will and should be a daily issue (not always a rape joke, but similarly serious complaints). That's why you have HR and legal departments.
And the next day? Workplace complaints take days or weeks to evaluate. Do not ever expect answers on the order of a day. In a really horrific situation you can ask your immediate supervisors for help, such as by transferring the alleged offenders elsewhere temporary, but do not ever expect heads to roll by next business day. The more serious the complaint, the more time one must expect before action is taken.