Two men at a fish market filled with boxes of fish and freshly cut fillets study a weight scale.
Two men work in a butchers shop, selling steak.
They can be either at a fish market or in a butchers shop. They can be either studying a weight scale or selling steak.
Fish is not steak. A fish market may not include the butchering step in selling meat.
The men cannot be at the fish market and the butchers shop simultaneously.