You know, somebody's hand has to do the removing, and there's a subpoena out now...some nurse is not going to want to get in the crosshairs of a Marshall, however much Greer might insist.
They must be served "in hand" and have proper legal notice of the subpoena. It "in hand" via a proper agent of congress or judiciary. It is not enough to just know about it.
What is the name of the hospital?
It is simple enough to find the name of the registered agent on http://www.sunbiz.org which lists all FL corporations and their agents designated to recieve service of process.