Hugo levi.
Your point would make sense if this had been the location team had staked out for capturing -- not killing -- the targets, including the Englishwoman who had joined El Shab'ab. They were waiting for her to arrive at the location before they gave Kenyan troops the green light to seize her. But only when an unidentified woman left the compound with some men did they suspect that she had been there all along. The party that had been meeting at the location then drove to a different location -- one under El Shab'ab control -- that had not been previously monitored in preparing for the operation.
The story is ingeniously plotted,