According to Official Guinness Records,
The fastest marathon dressed as a paramedic (male) is 3h 58min 17sec and was achieved by Karsten Koehler (Germany), in Torshavn, Faroe Islands, on 3 June 2017. Karsten attempted this record to raise money for the St. John Ambulance Charity.
For a complete list of 2017 records, please visit 2017 Guinness Records in Faroe Islands.