The bad thing is, Deveraux surrendered when his Marines were actually repelling the Japanese, because he had lost communication with his men and didn’t know what was happening. I’m certainly not accusing him of cowardice, and they would have been overwhelmed eventually, but it’s ironic.
You are correct. The marines had retaken some positions. I think what convinced Deveraux were the arrival of Japanese warplanes that continously circled the island and made further counterattacks impossible.