There is absolutely no reason that a rescue helicopter from Chicago would fly over 100 miles to central Wisconsin when there is a Level One trauma center in Milwaukee (Froedtert Hospital) on 30 miles away.
The goof items below may give away important plot points.
The episode ends with E.R. staff ribbing Abbey for her lax evening with the rescue crew, not knowing about her role at the bus accident scene. Yet they clearly knew about the crash since one victim was brought to County, and Abbey would have been present in the copter when the woman was unloaded; plus, County had been expecting the elderly heart attack victim, and would have been alerted that the copter diverted for another pickup. Plus it is hard to believe the crash got no media attention, such as a news copter on the scene, and plenty of episodes have shown the E.R. staff having the news on. The staff would also likely have heard some details of the crash from the first responders radio, and overall it could not fail to be broadly known that Abbey was at the crash scene.
As the rescue copter approaches the accident site and searches with the spotlight, the passengers ignore it, with nobody looking at it or trying to wave it down; and as Abbey is lowered to the scene--and even once she's on the ground--nobody calls out to her for help or tries to get her attention in any way for a decent while.