First, let me say that it is wonderful to see somebody still using a Mamiya C330!

Let's talk about feeling first. The title is Sanitarium, which leads a viewer to conclude the photo as something to do with the mentally ill. The crouched girl, with her hands folded, face down, frumpled hair does illicit this. The vague human figure at the end of the hall adds to the mystery of illness, a hallucination maybe.

Now let's talk composition. The shadowy figure is almost a direct bulls eye, which I rarely encourage unless used properly and you clearly have. The corridor echoes the rectangular doorway the figure is in and radiates wonderfully outward. The figure is clearly the center of attention and our eyes are brought to the crouching girl through one of the radiating lines. This makes the girl the secondary subject.

If it was your intention for the viewer to be engaged by the shadowy figure only to realize it may be a fantasy of the young girl then I would say you have done this brilliantly. If it wasn't your intention, then regardless your photo is quite compelling.

So let's talk color - or rather tint/shade since this is monochrome. The bright center works well with your compositional choice bringing the eye to the subject in the center. Choosing to include a darkened door in the bottom right was wise as the eye could be drawn to any four of the radiating lines but with a darkened area I feel that my eye automatically draws down to the bottom right to the girl.

I really have nothing bad to say. I would have chosen a slightly lower angle but that's nitpicking Nice job!