I shut it down again, and took my first step on the way of discovery.

In other words, I began my first examination of the four walls around me, and of all that they inclosed.
I was amazed at my own calmness.

My interview with Major Fitz-David had, perhaps, exhausted my capacity for feeling any strong emotion, for the time at least.

It was a relief to me to be alone; it was a relief to me to begin the search.

Those were my only sensations so far.
The shape of the room was oblong.