One of the more gripping scenes on "Mission Impossible 5" was Tom Cruise trying to hold his breath underwater for six minutes as he tries to get a computer chip.

"Normally in underwater sequences, people hold their breath for 10 seconds, 15 seconds max," he told Access Hollywood.

"So I had to prove to everyone that it was actually safe and spend time with the safety guys and the safety officers to show them not only is it safe, it's better that I know how to hold my breath because I'm going to be very relaxed," he added. "No one's going to have to rush in. No one has to panic."

In the same clip, freediving expert Kirk Krack said that he trained Tom Cruise in "breath-hold" special program designed for the military.

"What we're really trying to do is we're developing their ability to hold their breath under extreme conditions," he said, adding that Tom Cruise liked to challenge himself and had them worried a few times when he held his breath for much longer than the crew thought he could.

"You have to overtrain per sequence," added Katie Holmes' ex. "We were doing up to six and a half minutes breath-holds."

Tom Cruise if famous for insisting on doing his own stunts, and "Mission Impossible 5."

That can be a challenge to the stunt coordinator and the rest of the crew, just like Wade Eastwood shared to Variety as he said that it can a burden to keep a "megastar like Cruise" safe.

"Tom didn't want to have the feeling of being too safe. He said it would ruin his performance," he said.

He also talked about that underwater scene for "Mission Impossible 5" that Tom Cruise had to endure while training with a freediver.

"We didn't want cuts," Eastwood added. "We were looking for a claustrophobic effect. Tom really wanted to make the sequence difficult, and we wanted to take the audience on that journey with us."