Very creepy as doctors without morals is a pretty terrifying trope for a horror film – far more so for me, than the average crazed killer as there is rational thought behind the actions. In the latter part, the plotting seemed a little rushed as there were areas that it would have been interesting to explore re background, history etc. but I suppose this had to be sacrificed in the interest of the, generally tautly effective shorter running time.
The ending was chilling too as there was none of the usual final disposal of the villains as here the villainy was inbuilt and institutional and so likely to continue, even if there had been a temporary relief from it in terms of the lives of the central characters.