Yep, they needed the host country to send a helicopter to a US base overseas.
“...they needed the host country to send a helicopter to a US base overseas.”
All military activities at facilities used by US military forces in allied & other host nations are governed by a “status of forces agreement” (SOFA), negotiated with the host nation, determining who is responsible for what: eater supply, electrical power, trash removal, size & type of buildings, who building them, and in this case law enforcement.
Somewhat like inside the United States, there are differing jurisdictions covering different geographical and functional areas. If a given incident falls under the jurisdiction of the host nation, local law enforcement will respond, regardless of the type & capabilities of the US forces stationed there. Likely the case for this incident.
According to the official US DoD website, RAF Mildenhall plays host to KC-135, RC-135, MC-130,and CV-22 aircraft.