Stings and scams are passe by now on Bengal’s roiling political stage, but can an accident ask hard questions of a regime confident it will win a second term? It might be wishful thinking to see part of the under-construction flyover that collapsed in Calcutta’s Girish Park area as a metaphor for the Trinamool Congress’s fortunes in the assembly polls, but the tragedy offered the trifecta of CPI(M), Congress and BJP another chance of a lunge at TMC. Not that it caused even a wrinkle on chief minister Mamata Banerjee’s natural, confident pugnacity: she rushed back from outside Calcutta to manage the defence and promise punishment for the errant firm and compensation for the 21 dead (till going to press) and many injured.