Assuming there is a normal line for the shuttle (~E3-C7), that would probably be the quickest. If that's not the case, it really depends on your willingness and desire for a long run/walk (in most cases, you're probably not going to beat the shuttle, but YMMV).

(Typical shuttle you're probably looking at about 15 minutes; however, this really depends on your luck - I've waited for a shuttle for 20 minutes before. Running/fast-walking is about 20 minutes. With that said, I wouldn't want to go between these gates in anything less than 30 minutes, if not even 45.)