how dos shelley build suspense in these chapters?

The hastiness of Victor's wedding is indicative of his frantic desire to create an illusion of order and tranquility for his family. The narrator vows not to "delay the moment a single hour." His urgency fills the reader with an almost unbearable apprehension, since we realize that Victor is hurtling toward the consummation of his horrible destiny. For Alphonse and Elizabeth (and even, to some extent, for Victor himself), the event appears to be a means of safeguarding the future. Elizabeth and Alphonse cling to the idea of the marriage as to a raft at sea; they hope to salvage something of happiness from the senseless and unremitting tragedy.

Elizabeth, for her part, finds her joy commingled with an inexplicable foreboding of misfortune; in this way, Shelley foreshadows her doom. Victor seems to have temporarily lost the ability to reason; the decision to marry despite the creature's threat is nearly mad in its recklessness. In telling the story to Walton, he remarks that the creature "as if possessed of magic powers... had blinded him [Victor] to his real intentions." By this point in the novel, the creature has taken on supernatural proportions: it is as though he were the unleashed wrath of hell itself. Thus the earthly weapons that Frankenstein carries to protect himself against the creature seem futile in the extreme.

Significantly, Frankenstein compares himself and Elizabeth to Adam and Eve.

He says that his "paradisiacal dreams of love and joy" are dashed by the realization that "the apple was already eaten, and the angel's arm bared to drive [him] from all hope." This Biblical allusion has a number of ramifications. The apple of which Eve ate came from the Tree of Knowledge, which God had forbidden them to touch; it was for their curiosity that the first people were cast out of Paradise. Similarly, Frankenstein's misfortune befell him as a result of his overweening scientific curiosity and his desire to defy the work of God.

Frankenstein is aligned with both Adam and Eve, and, implicitly, with the creature himself: recall that the creature briefly compared himself to Adam during his reading of Paradise Lost. Strangely, this metaphor also serves to put the creature in the place of both God and the angel he is thus positioned as the creator of Frankenstein himself. Their roles are now utterly reversed.