Breed to Come by Andre Norton

rumbler?
    Would itindeed carry them on?
    "Brother!" Furtig bent over his tribesman. "Whatdo we do now?" But Foskatt lay with closed eyes, and did not answer. The stranger growled.
    "He cannot tell you. Perhaps he is near death. Atleast we are free of that hole. So—I shall make themost of such freedom."
    Before Furtig could hinder him, he jumped fromthe top of the servant and ran in long leaping boundsinto the dimness beyond. But, greatly as he wastempted to follow, the old belief that one ought not todesert a tribesman held Furtig where he was.
    He could hear distant squealing. More Rattonsmust be gathering ahead. Now he no longer believedthat the stranger had made the best choice. He couldwell be heading into new captivity.
    As would happen to them unless—Furtig pried atFoskatt's hold on the caller. Tongue tip had gone inthere, and the servant had come. Again tongue tip,and the rumbler had stopped beating down the wall.Therefore the caller ordered it. If that were so, whycould Furtig not command it now?
    He brought it close to his mouth. How had Foskattdone it? By some pressure like the sign language?Furtig knew no code. All he was sure of was that hewanted to get the rumbler away from here, back toGammage, if that was where it had come from.
    Well, he could only try. Gingerly, not knowingwhether the caller might punish a stranger without learning for attempting to use it, Furtig inserted histongue and tried to press. A sharp tingling sensation followed, but he held steady.
    There was an answering vibration in the box onwhich he crouched. The arms pulled back from thewall, and the thing began to move.
    Furtig caught at Foskatt lest he be shaken loose asthe rumbler trundled back from the wall and slewedaround, so that the arms now pointed toward the broken door of the room.
    They did not move fast, no faster than a walk, butthe rumbler never paused. And Furtig knew a new feeling of power. He had commanded this thing! Itmight not take them to Gammage as he wished it todo, but at least it was bearing them away from theRatton prison, and he believed that those slinkers would not dare to attack again as long as Foskatt andhe rode this servant.
    Foskatt's warning of the uncertain life span of theDemons' servants remained. But Furtig would notworry about that now. He was willing to take whatgood fortune was offered in the present.
    They slid away from the light of the Ratton-heldchambers. But now the nimbler provided light of itsown. For two of those arms extended before it bore ontheir ends small circles of radiance.
    This was not a natural passage like the cave ways; the Demons had built these walls. Furtig and thewounded Foskatt rumbled past other doorways, twicetaking angled turns into new ways. It would seemthat for all the sky-reaching heights of the lairsaboveground, there was a matching spread of passages beneath the surface.
    Furtig's ears pricked. They had not outrun, probably could not outrun, pursuit. Behind he heard thehigh-voiced battle cries of the Rattons. At least hewas well above their heads on the box and so had thatsmall advantage.
    Hurriedly he used Foskatt's own belt to anchor himto the arms of the rumbler, leaving himself free forany defense tactics needed. With the claws on hishands, he hunched to wait.
    Strange smells here. Not only those natural to underground places, but others he could not set nameto. Then the rumbler halted in front of what seemed ablank wall, and Furtig speedily lost what small confidence had carried him this far. They were going to betrapped; all this servant of Gammage had boughtthem was a little time.
    But, though the rumbler had halted, its outthrustarms moved. They were doing nothing Furtig couldunderstand, merely jerking up and down, shininground spots of light on the wall here and there.
    There was a dull grating sound. The wall itself splitin a wide crack, not such as those arms had beaten inthe prison wall, but clean, as if this was a portalmeant to behave in this fashion.