I was also at The Mall today but a little later than you. I find the two ground floor places cruisy also, but a little too busy. The one on the first floor, directly above Pizza Hut is quieter and more cosy. Good for meeting and greeting but unless you go to the pool area and use the shower rooms, not much you can do.
I was there to meet up with a GayRomeo contact who works on the 2nd floor in a hair place. Very warm and lovable guy. I was also on the look out for the Jeffer restaurant there, but according to the information desk, it doesn't exist.
However, while in the basement toilet in Silom Complex, I met my dear acquaintance Mon, who is a waiter at the Silom branch. he had on a 'T' Shirt that listed all the Jeffer outlets down the back. Some of the far flung outlets disappear below his beltline so he kindly lowered his pants so i could clearly see all the locations.(The Mall Bangkapi listed somewhere around Mon's 5th lumber region.) Hat Yai was close to his bottom. Their web site:
Jeffer Steak :: Think about Steak. Think about Jeffer! | คิดถึงสเต็ก คิดถึงเจฟเฟ*ร์ :: เจฟเฟ*ร์ สเต็ก :: Welcome
On the web site is a section for hiring staff. The requirements for a waiter are shown in Thai, but when translated by Google, they appear as:
"Education up to three meters.
With diligence and patience.
Love the clean and highly responsive.
Smiling and glowing with love put in service.
Shift work is defined by the company ."
or as Sextiler would say "Ready, willing and able".
I intend to travel to all their locations eventually and court any willing staff. So far I have been well inside the pants of one waiter from Chamchuri and one from Hua Mark on Ram soi 24.