Lukas Furtenbach, a famous mountain guide, helped a British team climb Mount Everest very fast. They used a special gas called xenon. The team left London on May 16, reached the top on May 21, and came back home two days later. This xenon gas helps climbers not get sick from the high mountains. But some people are worried about it, and officials in Nepal are checking if it is safe. Before the climb, the climbers trained in special tents and used the xenon gas in a clinic in Germany. Furtenbach thinks that spending less time on the mountain is better for nature. He also says that they did not use the xenon gas in Nepal, and he can show it is safe for climbers.