When you click on a footnote number, you are actually taken to the end of the talk. It is very inconvenient, but you can scroll back up from the footnotes until you find the place in the talk where that footnote is located.
Better than pressing the X-Close button, if you press the Back button on your browser, you will be taken back to the page where you selected the talk. At least that way, you don't have to sign in again.
But try just scrolling back up from the footnotes. If you keep in mind the footnote number, you will find your place in the talk more quickly.