Including the revamped episodes (Batman: Gotham Knights), this is the last Riddler-centered episode of the series. Paul Dini has since revealed that the reason for the limited number of Riddler episodes is that he was the most difficult character to write for, given that in the comic the Riddler’s plots go could on for issues on end whereas they have only twenty minutes in a cartoon episode. As a result, the production team has a bin filled with rejected Riddler scripts that proved too complicated or too silly to do.
The answer to how Batman escaped?
At the last minute he jumped into a large safe that was in the wharehouse.