Gung'f ubj vg'f jevggra va gur svefg rqvgvba. Qba'g xabj jurgure vg tbg punatrq va yngre irefvbaf.

I've always assumed that The Machine doesn't do this sort of thing because Harold went to a lot of trouble to make sure that it couldn't. Even setting up Thornhill and escaping from the government required it to be under attack at the time.

Spoilers for season 5:
Fnznevgna bs pbhefr vf haqre ab fhpu erfgevpgvbaf naq cebprrqf gb qb whfg jung lbh qrfpevor. Unebyq'f erfgevpgvbaf ner nyfb cerfhznoyl gur ernfba gung Gur Znpuvar vf hanoyr gb qrsrng Fnznevgna rvgure va gur erny jbeyq qhevat frnfba 4 be va fvzhyngvba va frnfba 5 hagvy ng gur raq jura Unebyq naq Ebbg erzbir gurz.

Eryrinapr zvtug or gur cbvag jurer Znex abgvprf gur qvssrerag pbybherq obkrf naq fgnegf gb cnl nggragvba gb gurz. Gur oyhr barf ner cerggl boivbhf nsgre nyy.