There were two now where they had been three. David's death had dismantled the triangle, and an enclosed space was now open. Two points are unreliable; with nothing to anchor them, there is nothing to stop them drifting in opposite directions. If it is string that binds, it will eventually snap and the points will separate; if elastic, they will continue to part, further and further, until the strain reaches its limit and they are pulled back with such speed that they cannot help but collide with devastating force.
