My theory is that the lull in missions was because the coalition began fretting over what would happen if the rebels attempted to enter and take Sirte. As a consequence we have cut them loose over the past two days.
From what I can ascertain the fighting appears to be taking place up and down the narrow corridor of the coastal highway. Gaddafi's forces seem well able to counter this - they know there's no danger the rebels will attempt to flank them, given their lack of training and equipment.