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 high places, but some people are worried about it. Mountain officials in Nepal are now checking it. The climbers got ready by training in special tents and using the xenon gas at a clinic in Germany. Furtenbach says that spending less time on the mountain can help the environment, for example, by making less trash. He also says that the xenon gas was never used in Nepal and that he can show it is safe for climbers.