Boiled shrimp? There's nothing fundamentally wrong with the idea you just wanna get it right. The rule I've heard for squid is "less than two minutes or more than an hour" because at like three minutes the proteins in them turn into rubber bands and it takes about an hour to break those rubber bands back down into food.
But if you don't clean them and you just throw them in a pot? For 20 minutes?
So here's the thing. Fish rely on an amino acid called trimethylamine oxide in order to keep their salinity correct against seawater. When they die, the bacteria on them start converting trimethlyamine oxide into trimethylamine. Trimethylamine is a common biproduct of bacterial ecology, which is why yeast infections smell... nautical. As my wife will say as we walk down the beach, her nose wrinkled, "smells like BV."
It wasn't so much the solids in that recipe as the side effects. It is generally recommended that shrimp boils be conducted outdoors.