I have not noticed that it was carpetted, but it is at a different location than the usual immigration. There is a separate entrance in the middle of long immigration hall. In other words, you need to walk maybe 50 meters in the public corridor past the normal entrance to immigration. And yes, you need the paper slip.

I have never seen a premium pax security lane enforced at a gate (i have flown dozens of times recently mostly MH). And the security machines are sometimes used for two adjacent gates. It can be a mess. My take is to arrive quite late at the gate when the line is shorter.