Steven Seagal has always been an ironically serene action hero. When he delivers a make-my-day wisecrack, his steely resolve comes nestled inside a velvet purr: He's like a cross between Clint Eastwood and Mickey Rourke. Now, in the brutally efficient Under Siege, Seagal, with his soft-spoken nihilist charm, attempts to move beyond limb-snapping exploitation and into epically scaled mainstream thrillers. He succeeds but only because this sort of slick action bash doesn't require a star with much personality. At this point, personality might only get in the way.
A brazen rip-off of Die Hard and The Hunt for Red October, Under Siege is set aboard a U.S. Navy battleship carrying nuclear-tipped Tomahawk missiles. Tommy Lee Jones, he of the creased face and obscene smile, has the demonic- terrorist-genius role. He smuggles himself aboard and takes over the ship; it's up to Seagal, as a former war hero turned staff cook, to launch a stealthy counterattack. In Die Hard, Bruce Willis, easing over catwalks in his bare feet, seemed to be taking tense human chances with every coiled move. Seagal, on the other hand, remains an invulnerable hulk, the kind of blasé superhero who can simultaneously grip one bad guy around the neck, kick another into submission, and use his free hand to pump bullets into two more. The difference between Die Hard and Under Siege is the difference between the adrenaline rush of true suspense and the jaded excitement generated by endless, mechanized ''thrills.'' B-