 In some of the exterior scenes, we see Carter and Benton walking  outside in their surgical scrubs, covered in sweat. This is real  sweat as it was filmed during a heatwave in Chicago. Even though  just prior to the scene, both actors had been in air conditioning,  the minute they stepped outside, they started sweating profusely.  This caused problems for Noah Wyle, whose character was suntanned  after a vacation. His tan (which was in fact make