Mandus's single-minded devotion to finding his sons is this. At least, it is before we find out what he did to them.
In the end, as Mandus lies dying, he hears church bells ringing above him in the city, and knows, for better or for worse, humanity has survived and is moving into the next century. The 20th Century, of course, will come with all the horrors and destruction the Engineer predicted, but humanity will still find a way to shine on through blood and hatred.
In the very last shot of the ending cinematic, we see two little boys running through the street, reminiscent of Mandus' sons.