Two Necessary Conditions Occuring Simultaneously

The video explanation for this question hinges on two necessary conditions occurring at the same time. Does this apply in all diagrammed logic structures? In some cases, this makes sense: Every Labrador is a dog L --> D Not D --> Not L Something could be a dog but not a Labrador, of course. However, in "Unless" structures, it does not make sense for me. For example: Unless it is Friday, I eat meat not EM --> Friday not Friday --> EM How would both necessary conditions (i.e., being Friday and eating meat) exist simultaneously in this scenario? Any help appreciated. Thanks!