I'm a bit confused as to what you are asking.
If you upload page.phtml to your server and it has username/passwords in it, calling page.html isn't going to show me the unparsed PHP code from page.phtml unless you've uploaded a copy of page.phtml as page.html...... they're 2 completely separate files after all. If all your files use either the .php or .phtml extensions, trying to load page.html is going to give me a 404 error.
Does this answer your question? If not, please repost the question explaining exactly what's happening on your server.
geoff