There are three “false” starts in Hezekiah’s tunnel that seem inconsistent with a “karstic channel” explanation. All of these false starts are in the immediate vicinity of the meeting point in the middle of the tunnel. Two are very distinct, penetrating as a rectangular indentation some 2 feet or so into the wall of the tunnel. The third is less distinct (it has a straight wall only on one side). All of them are found where the tunnel takes a bend. It can be argued that these are places where the original conduit divided into two branches. In these instances the “wrong” alley was followed first, but it was soon established that it was a blind one and was abandoned. The remaining question is why these false starts were so neatly hewn and finished. To this I may venture the following answer: Once initiated, whether or not by mistake, these recesses were enlarged and completed to their present form in order to serve a very important and useful function. The routine maintenance of the tunnel (cleaning and removal of debris) required “two-way traffic.” The tunnel is very narrow, and, along most of its length, there is not enough room for two people to pass. These recesses or niches solved this problem. In other words, these niches were part of the overall plan to begin with. Or they may have been adapted from false starts. Yet we must also ask why we do not find more of these niches scattered more evenly along the entire length of the tunnel. To this I do not have a good explanation.
Another problem is the frequent meandering near the meeting point. This may simply be the course of the original karst conduit. That is the best answer I can think of.