He did not allow himself to conclude that he heard the coffin-lid being opened from the inside.

He took his lamp and went to see what was wrong.
The sound ceased as he moved.

When the light of the lamp was in the next room all was perfectly silent.

For almost half a minute he stood still, shading his eyes from the lamp, while, with every disagreeable sensation crowding upon him, he observed distinctly that, although the nails were still holding it loosely in place, the lid of the coffin was raised half an inch, more than that indeed, at the top.
"Now, look here, you know--this won't do," said Trenholme, in loud authoritative tones; so transported was he by the disagreeableness of his situation that, for the moment, he supposed himself speaking to the man with whom he had just spoken.

Then, realising that that man, although gone, was yet probably within call, he set down the lamp hastily and ran out.
It seemed to him remarkable that Saul and the oxen could have gone so far along the road, although of course they were still plainly in sight.