We stayed at Base Camp for about five days. In that time we learned to move over difficult ground on simulated fixed lines, which was an extremely important learning process. In big insulated gloves, it takes real skill to use an ascender and belay plate effectively. We also learned to use our burners correctly. When boiling water at high altitude, especially in the cold, knowing how to use the burner effectively is the difference between getting a trickle of liquid, and a litre of water in an hour.
The trick really is to keep the gasses in the bottle warm and mixed. It takes constant attention and input from the people around it. The gas canister needs to be moved from side to side every few minutes to keep the gas mixed. It also helps to put the gas can in the water you are boiling, to heat it up a bit. You must use ice wherever possible, rather than snow. Snow has too much air trapped inside it, and yields very little water for the amount you have to put in the pan. Very inefficient.
Adding small amounts of ice and snow to the pan also makes a big difference. If you add it all at once, it creates an insulating effect, and wont melt. Crucially, you must always save a little bit of water from the last time you melted snow, to start the next pan going. It takes a very long time to get any water if you only put ice in the pan.
We also tested out our oxygen systems, which was a very surreal experience.