I don't get the huge staircase at the front of the aircraft, especially for SQ. As I understand it, SQ is very strict about keeping the classes seperate (i.e., business class pax stay in business, coach pax stay in coach). The "Grand Staircase" leads from main deck F to upper Deck C, so who would use it, and why? I can't imagine a horde of F pax wanting to rush up to C, and I didn't think C pax would be allowed down to F. Couldn't they replace it with a much smaller, space-efficient staircase (like on the 747) and use the wasted space for something else (bar in F?, seats in C?)