Thinking aloud, every market player has the right to sell or buy within limitations. I do not see anything wrong with Emkay's orders as an outsider. It is a legitimate order from their terminals - if they placed the order wrongly, we as outsider cannot question the order, and they take the responsibility.
But the point is the circuit breakers are not operated by NSE as per guidelines/ norms / rules at 10% and stopped it only by 16%. If it could not be controlled, then it is a fault on NSE. Above this, they violated again by restarting trading in 15 minutes. This is a willful activity for which NSE has to bear the responsibilities.
Finally and most importantly, this exposes the vulnerability (absolute lack of depth - A 650 Crore order, absolutely insignificant compared to the market cap of securities listed, can plunge the Nifty by 16%) of the markets!