Strategies for when your employees die

I had gotten to 4 and half stars and for some reason the hostess was fuming I didn't give her a promotion for the 2nd time that day and I had a waitress that suddenly was standing around.. I had the hostess walk off and I had fired the waitress.. it kept saying my restaurant was nonfunctional without them... I disallowed customers to finish off the day with the 1 waiter and the chef.. In the meantime I brought in new employees and did a training for each and closed. I did a quick open and close a couple shifts to help get them up to speed..

As far as a Chef, I had one of my families sell their successful restaurant for a new one to be built by scratch.. I didn't see my chef from the previous because the old restaurant still had him employed. So I had to employ a new chef.. I just assign speed to be careful, while they are building skill and getting a 2nd chef cooking carefully @ the same time works fine with 1 waiter.. My Sim just does more interacting and doing clean up.. but noticing those short shifts with no advertising helps gain some ground that was lost.