How does John Wyndham develop suspense in Chapter 14 of The Chrysalids?

One way suspense is built in Chapter 14 of The Chrysalids by John Wyndham is through selective revelation. This technique is easy for Wyndham to achieve because the point of view of The Chrysalids is a first person narrative rendered by David, therefore the reader only knows what he knows, sees what he sees, feels what he feels, etc.

In Chapter 14 David regains consciousness and slowly becomes aware of his surroundings and of events occurring around him. That is the suspenseful way in which he and the reader both learn that he and his friends are being taken prisoner by the deviant mutants of the Fringe. A similar technique is at work when David learns the identity of the spider-like man who bears a striking resemblance to David's father Joseph Strorm. David and the reader both learn together that this spider-like man is indeed Joseph Strorm's brother and David's uncle.