If you were lucky this week, your only exposure to the excruciating temperatures was a series of coat-hugging sprints between a car and a warm building. Tiffany Mingo was not so fortunate. She is one of the 33 mail carriers working out of the Lancaster Post Office on North Main Street. They’ve battled day after day of sub-freezing temperatures and whipping winds to complete their appointed rounds as swiftly as possible.