Albert Barnes Commentary Acts 27:42

"And the soldiers` counsel was to kill the prisoners, lest any [of them] should swim out, and escape." — Acts 27:42 (ASV)

And the soldiers' counsel, etc. Why they gave this advice is not known. It was probably, however, because Roman military discipline was very strict, and if the prisoners escaped, it would probably be charged against the soldiers that this had occurred through their negligence and unfaithfulness. They therefore proposed, in a most cruel and bloodthirsty manner, to kill them, though contrary to all humanity, justice, and laws; probably presuming that it would be assumed they had perished in the wreck.

This is a remarkable proof that people can be cruel even when experiencing the tender mercy of God; and that the most affecting scenes of Divine goodness will not mitigate the natural ferocity and cruelty of those who delight in blood.