The lovers who flew from prison in a stolen helicopter pleaded innocent to escape charges, and their lawyers said they would argue for acquittal on the grounds that the escape was justified. But lawyers for Samantha Dorinda Lopez and Ronald J. McIntosh declined to explain their justification for Lopez's Nov. 5 aerial breakout from the Federal Correctional Institution at Pleasanton. "Ms. Lopez has a story to tell . . . that is poignant in some respects and is tragic and frightening in others," said her lawyer, Geoff Hansen, an assistant federal public defender. " . . . Her leaving Pleasanton will be justified in the eyes of the law." Authorities said McIntosh, 42, who fled Oct. 28 during an unescorted transfer to another federal prison in Lompoc, hijacked a helicopter at gunpoint, landed in the prison recreation yard and flew off with Lopez, 37. They were arrested Nov. 15 while picking up wedding rings at a Sacramento area shopping mall.