Heroes Rise: How the Riddler Got His Name - S3-E15
Continuity mistake: Edward Nygma rolls gas canisters down the aisle at the Gotham Police Academy speech, the canisters land on their sides, then suddenly they are standing upright, spewing gas.

Starring: Sean Pertwee, Ben McKenzie, Donal Logue, David Mazouz, Camren Bicondova, Dean Morris, Jon Beavers
Heroes Rise: How the Riddler Got His Name - S3-E15
Continuity mistake: Edward Nygma rolls gas canisters down the aisle at the Gotham Police Academy speech, the canisters land on their sides, then suddenly they are standing upright, spewing gas.
A Dark Knight: Queen Takes Knight - S4-E11
Bruce Wayne: Alfred, you're fired.
Question: Trying to remember which episode had a literal 'black market' - crooks were pushing shopping carts down isles with signs indicating which contraband was stocked in which isle.
Answer: "The Merc" was a warehouse like store with aisles that sold mainly weapons, machetes, AK-47s, C-4, barrels of acid, etc. In s02e05, "Scarification", it was shown being raided by GCPD.
Bishop73