The Gilgamesh. Jack trilogy, #2

Jack Kamping had one morning of peace on the island where his friends died. Then the seaplane came. General Skyler doesn't want Jack dead. He wants his blood. Four hundred feet under the Nevada desert there is a dome built to make a captive animal believe it has sky. What lives in it has never been controlled. Skyler thinks a man with alien DNA might manage it. Jack counts alarm panels and looks for a way out.
Above him, Kim Holland and two strangers are converging on a desert town called Rachel, none of them knowing there is an explosive charge implanted beside the creature's heart. He was told he'd be free in a week. He was told a lot of things.