Picking up where his True Lies persona left off, Arnold Schwarzenegger is once again a cool, confident, superheroic G-man in the trailer for Warner Bros.’ Eraser (due June 21). It’s hard to top nuking the Florida Keys and wrestling a jet fighter, as he did in 1994’s Lies, but here Schwarzenegger sows chaos (and upholds order) by bursting through industrial-strength flooring with guns blazing and breaking glass to put a tankful of alligators into play. For all the sound and fury, the trailer never does really tell us what the movie’s about. The truth is that Schwarzenegger plays a U.S. marshal who specializes in witness protection. The witness in question: Vanessa Williams. But the narration plays at a true lie: ”He works for a secret government agency. He answers to no one. He’s called in when time has run out. To save your life he must eliminate every trace of your existence…to protect your future, he will erase your past.” As for sample dialogue — well, there’s only one line: ”Relax,” growls Arnold. ”You’ve been erased.” Hasta la vista to you, too.