Gods of the Jungle by Nelson S. Bond

It mattered little to Ramey Winters that the smallest of the followers of Ravana towered a good head and shoulders above himself. Given a moment's time to prepare for trouble, an opportunity to set himself, he would have gladly matched his wits and strength against that of his captors. If brute power alone were to be considered, neither he nor any Earthman could stand against the giant Videlians. But he had in his belt a Twentieth Century weapon that was, indeed, as the gangsters of Ramey's era had termed it, an "equalizer".

But he did not draw his automatic. The attack was too sudden and too unexpected. and by the time he felt hard Videlian hands upon him he did not need the mutely warning glance of Sheng-ti to remind him that this was one time the adage about discretion being the better part of valor well applied.