I've walked between T6 and T7. In addition, when AA was split between T4 and T6, it took me less than 10 minutes - more like six or seven - to walk at a normal pace from the Admirals Club in T4 to the T6 gates. After the four T6 AA gates were moved to T5 and the T5 AC opened, it took me no longer than four minutes to walk between the T5 AC and any gate in T4.