Ponderosa is the name of a restaurant chain. They pride themselves on their prime rib` (a specific cut of beef). When many people come to a buffet, they form a line, and if the speciality most people came for runs out while people are still queuing, that may lead to some very dissatisfied customers.
I would guess that the anchor either worked in the hospitality industry before, or reported on some brawl that broke out because of something like this, and thus felt there was a similarly life-threatening quality about this... or it was meant to (jokingly?) downplay the threat of Cov19.
The sentence might get more palatable if you remove one 'the':
"Ponderosa suddenly out of prime rib in the middle of the buffet line"