The Florida Everglades are the eerie setting for the author's second medical thriller ( Pulse was the first); he's mystery writer W.R. Philbrick, writing under a pseudonym. Emile Vidoc, brilliant medical doctor and psychopath, finds a combination of drugs that turns young men into wild, demented ``fighting machines'' who can feel no pain. He hopes to fuel guerrilla warfare in Central America, and to make a handsome personal profit. But his scheme is discovered by a public health physician in Miami. When she teams up with a Missing Persons detective, the two encounter Vidoc's ``recruits,'' lying comatose in an abandoned van. A lively pace, crisp writing, and a twist at the end make the book better than average, but its overdose of violence may upset some readers.-- Joyce Smothers, Monmouth Cty. Lib., Manalapan, N.J.