This, then, is the last time, short of a miracle, that henry jekyll can think his own thoughts or see his own face (now how sadly altered! ) in the glass. nor must i delay too long to bring my writing to an end; for if my narrative has hitherto escaped destruction, it has been by a combination of great prudence and great good luck. should the throes of change take me in the act of writing it, hyde will tear it in pieces; but if some time shall have elapsed after i have laid it by, his wonderful selfishness and circumscription to the moment will probably save it once again from the action of his ape-like spite. and indeed the doom that is closing on us both has already changed and crushed him. –the strange case of dr. jekyll and mr. hyde, robert louis stevenson
in four to five sentences, explain how this passage connects to the theme "evil can never truly hide itself."