The simile like a splash of cold water shows that Samuel is feeling D. Strange and distressing.
Samuel shakes off his fear by reminding himself that he is D. busy and safe where he is.
The effect of the simile
Just as a splash of cold water can be startling and uncomfortable, this simile conveys Samuel's sudden and unpleasant realization. The awry scenery disrupts Samuel's emotional state, leaving him feeling unsettled and uneasy as he thinks about the people in Jamestown.
But in the latter part, Samuel shakes off his fear by reminding himself that he is busy and safe from the troubles.