Welcome to flyertalk oholz.

When I flew int'l out of BKK in Dec, it went check-in counter, pay 500b departure tax, passport control area, then you were in the D shopping hall. The TG lounge was a down-escalator ride (presumably to lvl3) from there. Quite nice. Back up the escalator when it was time to board. Baggage security screening occured at the gate area, past the shopping zone.

Incidentally, at SIN I noticed the same thing: an open shopping area, with security/baggage checkpoints at the boarding gate.