I wouldn't bet on that. Yes, the train won't leave either the conductors or the engineer behind, but the on board service crew could get left behind if they're not careful. Now in the case of the chef, I would figure that he told one of the conductors what was happening, so it is unlikely that he'd get left. But if he didn't tell a conductor, then they won't be checking to see if he's back on board, they'll just go at the appointed time.
A few years back on an OTOL fest our sleeping car attendant almost got left behind at Houston. Seems that a conductor had come by and locked the door to the sleeper from the inside, but never looked outside to note that the attendant was still out on the platform. There was also some speculation that there was some animosity between the two and that he did it deliberately, but that's not confirmed.
In any event the attendant was lucky that NJCoastEXP was in his room on the lower level and still awake. She banged on his window to get him to come open the door for her so that she could get back onboard the train. Had he been asleep or had he not known how to open the door, the rest of the car would have awoken the next morning without an attendant.
