Sometimes, when I'm all alone doing my work because my
colleagues are in the other rooms, and if I see / sense something,
I will usually try to ignore it and mumble under my breath to leave
me alone, I'm just trying to get my work done. 
I had a very very frightening encounter once that spooked my
colleagues too. We had a long-term patient, an elderly
Chinese lady who's lost her wits and is crazy, stay with us for a
long time. Because she was nuts, we had to restrain her and
she used to scream and yell and kick and curse at us. Months
later, after a few hospital admissions, in and out, she passed away
in our ward. A few days later, when I was working nights, I
was writing my report when I drifted off to sleep without realising
it (I was still holding my pen upright 
). I saw her standing at the corner,
pointing at me and scolding me for restraining her. Then like
a ghost, she moved closer and closer to my counter! Suddenly, I gasped very loudly and snapped out
of it. My colleagues at the counter were alarmed, all looked
at me and asked me what happened. 
I told them and they said, if I see her
in my dreams again, just tell her that she was crazy so no choice,
we had to restrain her lor. 
Reminds me of "The Eye" movie. The actress was seated, trying to
learn caligraphy from where she saw someone standing at the corner
or the room. That "someone" said "why are you sitting in my chair!"
Then suddenly the "someone" dart towards her with arm
outstretched!
I guess me quite lucky. Never had any serious encounters in any
hospitals or army camps. The most spooky was having the feeling
something else was around, and noises & knockings in a hotel
room.
