The ending seemed obviously surreal to me so I was inclined to believe that it was just what he was imagining as he was dying - but on an abstract level, there's a different way to read it; throughout the movie, there are many parallels between the destruction of Toller's body and the destruction of our planet, and I think the ending was supposed to symbolize that uncertainty of not knowing whether we're headed for imminent extinction or not.
I'm not sure if I like this kind of thing (I guess I'm kind of a literal-minded person who dislikes allegory) but this is my read as to what was intended. That said, the ending feels like death to me, largely because of the Lustmord music playing over the credits.