"Panic Button" resident on every page in case abuser walks in the room

Hey Everyone,

I am busy developing a site for a charity that offers advice, telephone support etc to people who are being abused. A feature request has come through to have a button permanently available on every page. This enables the reader to click the button and immediately close the current charity website and open something like google or msn.

This is useful in case the abuser walks into the room or is nearby.

If anybody has some previous experience in this area I would be grateful to hear from you.