Consider an urgent care center with $4$ doctors where the average arrival rate for each doctor is $24$ patients per hour and the average service time of each patient is $2$ minutes. Both inter$-$arrival times and service times have a coefficient of variation equal to one. Initially, each doctor serves his or her own patients. How many minutes does a patient spend on average in the urgent care center $($including the time waiting in line as well as the actual service$)?$