Linkin Park - Shadow of the Day Lyrics Meaning

I heard a shocking story about this song: The band had a concert (unfortunately I do not remember where) and just a few weeks later they watched TV and saw the place where this concert was. Then they wrote this song.

I close both locks below the window.
I close both blinds and turn away.
Sometimes solutions aren’t so simple.
Sometimes goodbye’s the only way.

Actually they don't want to believe in this, they don't want to see it, so they close the blinds of th window. But they have to accept this event.

And the sun will set for you,
The sun will set for you.
And the shadow of the day,
Will embrace the world in gray,
And the sun will set for you.

The sun will set to let the world be shaded, to let the world lament.

Pink cards and flowers on your window,
Your friends all plead for you to stay.

Actual everything should be so nice, and though nobody is happy about this occurence, it cannot be averted.