The Sarnia Fire Rescue Service was busy early Thursday, responding to two separate fires, one of which required a rescue.Crews were called to a single family home on Wiltshire Drive at approximately 9:25 a.m., near the intersection of Murphy Road and Michigan Avenue, and were met with heavy smoke and flames venting from the second storey.The fire department said four occupants had escaped prior to their arrival, however, one remained unaccounted…