The film is shot in Fiji waters, said to have around 35 different species of sharks amid dangerous currents. Sinha understood that perils of the underwater world cannot be taken for granted, and so he roped in experts for his film.
The actors could shoot only for a certain number of hours in a day in line with the time and temperature of the water so they wouldn't fall sick. International action director Dave Judge and safety advisor Tack Baldwin were responsible for the actors' well-being.
A shark handler was also roped in for the film. Apart from them, local divers were present in the water with the actors at all times. During the scenes with the sharks, safety nets were placed between them and the actors.
Sinha says these measures were vital.
"Our primary objective was to ensure that the cast and crew were absolutely safe. We took all possible measures, not cutting back in any way. Hence, we were able to successfully complete the shoot within 42 days, with everyone in perfect health," he said in a statement.
Directed by Gurmmeet Singh and co-produced by Sunil Lulla, "Warning 3D" is a journey of seven friends in a life-threatening crisis. Starring young actors Santosh Barmola, Suzana Rodrigues, Varun Sharma, Manjari Phadnis, Jitin Gulati, Sumit Suri and Madhurima Tulii, the movie will release Sep 27.