The Hindi track in a proper WEB-DL is usually synced perfectly to the video, unlike random YouTube uploads.
Sergio is usually calm. But the death of Nairobi breaks him. He abandons the plan. He abandons logic. He initiates a suicidal war against the army. This leads to the massive explosion sequence where the gang uses a tank of liquid nitrogen and a bomb to blast open the vault, literally burying their enemies in gold.
(Great, with minor technical notes)