Princess of Chaos by Bryce Walton

The tribes from which Moljar came were fatalists. Moljar accepted the fact that he was face to face with imminent death. Very well. If there was a way out, he would find it. If not, he would go on to Khles, where dead warriors go. And from Khles he would fight his way into the eternal paradise of Perlarh.

He had expected the gyro to float at least a few minutes. But it sank almost immediately. The shock of the crash had knocked Mahra unconscious; pulling her against the suction as the gyro went under was a herculean task. The crumbled wreckage went down. It left only a tiny whirlpool in its wake.