And they had no power. Literally, no hands. Our version here follows the Arabic, Syriac, and Chaldee versions. The LXX. and Vulgate render no direction in which to fly. But in this case לָהֶם would seem preferable to בָהֶם.
The Vulgate translates the last clause of the verse, "Praesertim cum hi, qui simulaverint fugam … fortissime restitissent." They could not flee back to the city, for it was in flames. They could not advance northward, because the Israelites had faced about and were coming to meet them.
To flee in any other direction would be to cut off the last hope of saving the city. For יָד in the sense of side or direction, however, see Exodus 2:5; Deuteronomy 2:37, and especially the dual, as here, in Genesis 34:21; Isaiah 33:21.