Lukas Furtenbach, a famous mountain guide, helped a British team climb Mount Everest very fast. They used a special gas to help them. The team left London on May 16, reached the top on May 21, and came home two days later. This gas helps climbers not get sick when they are very high up. But some people are worried about it, and officials in Nepal are checking it. Before climbing, the team practiced in special tents and used the gas in a clinic in Germany. Furtenbach thinks that spending less time on the mountain is better for nature. He also says the gas is safe for climbers and was not used in Nepal.