Elmhurst Hospital in Queens never volunteered to be the poster child for Covid-19 disfunction. But the role was thrust on it in the early days of the pandemic because, as the biggest public hospital in New York City's most ethnically diverse borough, Queens, it had no choice. On some of the coldest days of the year last March, the line in the street to get into the ER never disappeared. The flow of patients was a steady drip.