Complex sentence: At the second event in South Korea, an estimated 100 riot police stood guard at Incheon International Airport to prevent harm from happening to Ohno stemming from fears of a lingering negative reaction from the 2002 Olympic Games disqualification controversy.
Split into simpler sentences: At the second event in South Korea, an estimated 100 riot police stood guard at Incheon International Airport to prevent harm from happening to Ohno. Their concern stemmed from a possible lingering negative reaction from the 2002 Olympic Games disqualification controversy.