Seated in the comfortable office of a distinguished Baltimore law firm, former Maryland governor Marvin Mandel and four of his codefendants discussed their continuing legal battle yesterday and took up the subject of legal fees - which sources said already exceed $1 million.

To continue the fight by appealing again to the 4th U.S. Circuit Court of Appeals and possibly the Supreme Court would cost another $100,000, they were told.

"We had to have a little shot of oxygen after that," said one man involved in that long-running legal drama - U.S. vs. Marvin Mandel et al.

The saga already includes one mistrial, one conviction, one reversal and one reinstatement.

Twelve days ago, a federal appeals court reinstated the convictions of Mandel and his five codefendants on mail fraud and racketeering charges, setting the stage for yet another appeal.

Mandel and his codefendants were convicted on political corruption charges after prosecutors accused the then-governor of accepting $350,000 in gifts, vacations and stock in return for secretly using his office to enrich his codefendants' business interests.

Yesterday, a bevy of lawyers and all but one defendant met in the law offices of Arnold Weiner - Mandel's attorney and their lead counsel - to talk legal strategy and legal fees.

The lawyers have decided to return again to the 4th U.S. Circuit Court of Appeals, which reinstated the convictions by a 3-to-3 vote July 20. But this time they are hoping that two new judges - one who was sworn in last week and one going through Senate confirmation hearings - will participate in the decision, sources said.

If that fails, they'll take the case to the U.S. Supreme Court, a move that would cost more than $100,000, according to one participant in yesterday's meeting.

But despite the latest financial prediction during yesterday's three-hour meeting, nobody argued that the appeal should be dropped, according to one defendant.

"It's like being told you gotta have an operation to save your life," he philosophized. "You say, 'That's it. Go ahead and operate.'" CAPTION: Picture, MARVIN MANDEL . . . plans continuing appeals