We don't.
It seems unlikely to me though. He said that Alexis went out the back door into the parking lot at 11:30 PM, right? From that BoomerJack's website it looks like they're open until midnight every night. So I assume there would have been more staff there until at least midnight. I guess they could have closed early, but that seems unlikely on a Saturday night.
She went missing the night of the Super Bowl - correct me if I'm wrong - and I want to add that the Super Bowl was a blowout. I don't think this place would've been all that busy, especially during a pandemic. If the Cowboys were in the Super Bowl, would be a different story. So there probably weren't too many people around IMO and Lexi could've gone out the back pretty easily. The part that sticks out to me with the cook is not confirming she "got in the car". But we just don't have much to go on. I find the entire situation strange. If DC learned something since the interview he gave, wouldn't he tell the public? If he has heard nothing since the interview, wouldn't he still be updating the public regularly, and trying to get the word out even more? Just thinking out loud. Not blaming anyone.
I just hope Lexi is safe. If she is with her mom like some have speculated, I can see why this story would receive less media coverage/would be strange for the family/LE to discuss. I haven't seen the SM post that references the possibility, but if she is with her mom or if the dad does know who Lexi where Lexi is, why the billboards? An update from anyone would be great. Confirmation of Lexi's safety would be better.