Exodus 14:23

Egyptian pursued.

It is by no means clear that the Egyptians knew or thought they were following the Israelites into the bed of the sea. Considering the darkness, additional to that of the night, which had been superinduced between the pursuers and the pursued, it is not probable that they had any clear perception of the course in which they were moving, and least of all, that they imagined themselves traveling on the bared bed of the divided waters.-- Bush.

To the midst of the sea.

The Egyptians naturally followed close upon the Israelites, from whom they were only divided by the pillar of cloud and fire; and when the rear of the Israelites had reached the opposite shore they were in the midst of the sea.