Starting the day off right

So, I'm reading a review of this book in Publisher's Weekly, and they say it has some overwrought prose. This was their example:

"The relationship had begun to bleed, exsanguinating as relentlessly as a slit wrist in a warm bath."

What the HELL does that mean?! This is a mystery book for crying out loud! PW was the master of understatement on that one. Overwrought.