Atlanta-based Grady Memorial Hospital is engaged in a six-figure fight with a New York doctor who said the hospital hired him as a top administrator, moved him to the city and then killed the deal the day before he was to start work. William Bithoney, MD, said hospital officials misled him and then stranded him, personally and professionally, in Atlanta. Bithoney says Grady owes him $612,500 in severance pay, and a lawsuit seeking damages could drive that amount to more than $1 million.