I guess my pysche is a bit of a slippery slope in the dark.

SW

How about "scared in the dark."

I have been there.. Observing alone in the mountains near the
California-Mexico border. The forest ranger once told me that when I am there,
it forces the guys who smuggle drugs/people to move their drop off point
somewhere else.

Totally engrossed in the eyepiece, a loud noise startles me, the adrenaline
pumps and I have the shakes. It was probably just a branch falling or a animal
in the bushes, but the effect is the same as if it had been smuggler laying in
wait....

That was the end of my observing session for that night but I didn't have any
trouble being sleepy for that 1 hour late night drive home.

Jon