Lukas Furtenbach is a mountain guide. He helped a team from Britain climb Mount Everest very fast. They used a special gas called xenon. They left London on May 16. They climbed the mountain on May 21. They came home two days later. This gas helps climbers not get sick on the high mountain. Some people do not like the xenon gas. People in Nepal are checking if it is okay. The climbers trained in special tents. They also used xenon gas in Germany before they climbed. Furtenbach says climbing faster is good for the mountain. It means less trash. He says the xenon gas is safe for climbers. He also says they did not use it in Nepal.