Every time I pass through LAX on my way to another country, I check in with my carrier (usually CX) and head back to the right corner to go through security.

First you talk to a contractor who puts you in the correct line, then you go down a short hallway and talk to the TDC. As recently as about a year ago you could still do an SDOO by keeping to the left after the TDC (source). But some time in the past year LAX/TBIT switched to 100% NoS machines there (well, they still have a WTMD, but it's hardly ever used, even during peak times).

What's interesting is that once you get close to the machines, if you look off to your left, there is another separate "secret" screening area with only WTMDs and no NoS machines. They generally don't take people off the main line, this area has it's own separate entrance. You can see it after you get through security if you look backwards towards the entrance.

On my last trip through TBIT I looked all around for the entrance and I couldn't find it (before entering the checkpoint), which leads me to believe it's only for people with medical complications or VIPs or something. It definitely did not appear to be in use by pilots or FAMs. I tried handing the initial contractor my TSA Notification card (describing my TSASS, of course) but they didn't even want to look at it, just said show it to the next guy. So they definitely aren't directing all medical cases over there, maybe just severe ones?

So I'm wondering, has anyone else noticed this? And what is the policy that determines who gets put in that line?