It's not about death or suicide. It's an allegory for a depressive episode. Death Valley is a deep geographical depression. Read the lyrics.
Lyrics
You think
There's no power here
Nothing but emptiness
So you look deeper and deeper
Each time lower than before
And you're lost
Is it better to turn back?
Or continue through?
There's no telling
It's the gravity
That pulls you down
Like a whirlpool
Of dry wind and sand
Suffocating
To the bottom
The ground is too hot
You can't bare to stand
So you spend most of the time in the air
Dreading each step
The thirst to live grows exponentially
But it's futile
There's no quenching it
Your body dries up
You grow feeble
Mirages appear
Central air-conditioning
An in-the-ground pool
And now they're gone
The wind and sand rip away your flesh
Leaving mindless bones
The sunshine still burns you
--lyrics and all music by matthew john mortimer