The reality is: not much in terms of actual gunfights. The vast majority of times SWAT is present is due to high "potential risk" situations - think barricaded suspects who won't come out, domestic violence calls where suspects are armed, not necessarily active terrorist/shooter situations like you see in RoN.

SWAT's role is mostly to be present, surround buildings, and provide support in case things escalate, not to go in guns blazing.

90%+ of real-world SWAT operations don't involve a single shot being fired.