Due to the delay of Malaysia Airlines' flight from Penang, I was in a rush and at the gate, there was a MAS staff to which I told my situation that I could not make it to the check-in counter at level 3. She told me to go to the MAS' counter at the end of the terminal before going back into the main terminal.

There, a staff helped by making few calls to confirm my presence and gave me a handwritten ticket to allow me to pass the immigration. He told me that Thai Airways will provide me proper boarding passes when I get to the gate.