I recently got 60,000 proactively offerred because of a stain in the carpet and the poor communication between staff to fix it. You got 5000 for having some stranger's urine in your bed and the failure of front desk to recognize a biohazard and unacceptable conditions to immediately change your room assignment.

I am happy you are fighting this. Share your photos with Marriott corporate and don't take their first offer. This is insane and not acceptable at any Marriott brand, of any star rating, or in any country. At this point I would hold out for a full refund for the night + a goodwill gesture.