Playwright Roffey may not know much about thrillers, but he certainly can throw a cataleptic trance.
Whether or not Yogis can "induce cataleptic rigidity in a limb or in the whole body" is irrelevant here: it would require not even an "unbelievably strong" man to stiffen .
Rahman Bey, fakir, recently submerged himself for an hour, asserted that he owed his life to his ability to fall into a cataleptic trance.