Here is the full list of all 14 Men's Room Mayhem trophies - there are 11 bronze, 2 silver and 1 gold.
Complete All Gold Objectives
Survive 3 waves with a full mayhem meter
Have 12 patrons on screen at once in Blitz Mode
Complete All Silver Objectives
Serve the Clown Twins at the Circus
Serve the Bully at the Beach
Complete All Bronze Objectives
Serve the Hippie at the Festival
Serve the Drunk in the Biker Bar
Serve the Woman in the Nightclub
Serve the Old Man in the Hotel
First full cleanup (all toilets and sinks cleaned)
Survive 3 waves with everyone washing their hands
Serve Your First Patron