I can't sign out of Bungie.net, anyone know why?

This isn’t advertising, so please don’t flag it. I’m trying to download maps from Bungie for Halo 3, but I forgot I already had an account linked to my gamertag and made a new account. Later, when I couldn’t link my new one, I realized I already had one up. So now I’m stuck in this account that has no gamertag linked to it and I can’t link it because my other already is and it won’t even let me log out. I check “saved passwords” in my Firefox options, but Bungie isn’t even on the list. When i click sign out the page just refreshes and leaves me signed in. The only way I can get on my actual account that is linked is to open a different browser, but I don’t want to do that every time I want to download a new gametype or map.