On the Gobi desert set of the period action flick Dragon Blade, crew and actors would take off for toilet breaks - and then not come back.
Action superstar Jackie Chan, 60, soon found out why he himself had to use the facilities.
"Even the horses would know to seek out the shade and you could see people hiding under vehicles for a snooze. There was simply no shade to be found and even tents that were put up would be blown away when the winds came," he recalls in an interview with Life!.
Temperatures fluctuated from below freezing point in the morning to a brutal, more than 50 deg C in the afternoon and actors had to be clad in heavy costumes and armour.
In the film, he plays the commander of the Silk Road Protection Squad who champions peace among tribes of the region. It opens here tomorrow.
The US$65-million (S$88-million) film was a massive undertaking involving 350 crew members, 800 extras and 200 horses.
Chan even wanted to use Tibetan mastiffs, a powerful breed of dogs used by Mongolian conqueror Kublai Khan in battle to bite the legs of enemy soldiers. But he says regretfully: "They are too scary and we couldn't even control one single mastiff. How to film in that case?"
Despite the huge budget, reportedly the largest ever for a Chinese film, he professes that he does not feel too much pressure about its success.
"In the past, I would compare the box office of my films with those of Sammo Hung and others. But today, it's not about beating anyone. It would be best if everyone did well."
Of course, he has a proven track record to bolster his confidence. Even with the popularity of special effects-driven blockbusters such as Transformers (2007- 2014) and superhero flicks, his movies have continued to do well.
"I have kept to my Jackie Chan, very stupid style of making movies. And it is because I have stuck to the old-school way of doing action flicks that I can still have a place in the top tier of this genre.
"It's a miracle. I guess it proves I've taken the right path."
The veteran star is known for giving his all when it comes to his movies - risk to life and limb be damned. While he has slowed down with age, he remains committed to giving fans an epic cinematic experience every time.
While there were no close shaves this time, action sequences could still be dangerous.
In one scene, Chan is crossing swords with Hollywood actor John Cusack, who plays Roman general Lucius.
He recalls the shoot: "When he brought his sword down on my helmet, he used every ounce of his strength and I almost passed out. And I couldn't go 'Aiyah'.
"My style of fighting looks like it uses a great deal of force, but it doesn't hurt you. Whereas his strokes can be very painful even though it might not look like he's using a lot of strength."
Chan took it all in his stride though. Already, he cannot remember the injuries he suffered while shooting Dragon Blade, given that his filming schedule is so packed.
Immediately after that, he went straight into Skiptrace, an action comedy film directed by Finnish film-maker Renny Harlin.
"Injuries are something I sustain every day on a film set and I'm used to them," he adds.
Even if he gets hurt, he remains the big brother on set and is the one taking care of the welfare of others. He even personally spent "a few million", presumably in Chinese yuan, on coffee, tea, soda, biscuits, bread, cake and ice, all available around the clock.
So, given that the cast includes Hollywood stars such as Cusack and Oscar-winner Adrien Brody, who had the biggest trailer on the set?
He answers without hesitation: "I kept the best for all the foreigners. I would do my make-up in the public dressing rooms for all to see."
Many of the extras were not professional actors, but foreign students studying in China who were recruited to play Roman soldiers.
Chan says: "I wanted the set to feel like home to them so that they would be very comfortable and think that filming in China was really not bad at all. I didn't want to give them a bad impression."