Practical Travel Safety Issues - Pre Line Question

I'm Nexus/Delta Gold & a US citizen. In Detroit (domestics), I always get pushed to the Pre Line. Last night, I'm flying out of LAS and was upgraded to FC. I headed over to the First Class line with Mrs. D.S. in tow (who also has status and Nexus). There is a pre-dedicated line right next to the FC line. Her pass gets beeped three times and goes through Pre, mine doesn't and I have to the regular way.

I get the random checks and there is no guarantee for Pre. My question is whether I would still get to go through the expedited line (albeit getting run through the regular search)?