How does the author use foreshadowing in R.U.R.?

The author uses the literary technique of foreshadowing in Act III when Busman enters the drawing room with his arms filled with ledgers so that he cannot see the electric cables that Hallemeier and Fabry have brought in. The men yell at Busman to watch out for the cables, and he sidesteps them. However, near the end of the act, Busman is killed by the electric cables that line the fence where he stands attempting to negotiate with the robots. Symbolically, mankind's own technology is the means of death.