The opening scene of act 4 achieves a mood of absurdity through the conversation that takes place among Tituba, a slave; Sarah Good, a homeless woman; and Herrick, the town marshal. Tituba and Sarah claim to be waiting for the Devil to show up to take them back to Tituba's home in Barbados. Herrick is drinking on the job, as things are so miserable, and he even offers some to the prisoners.
The fact that Tituba now wishes for the Devil to come and take her away from Salem shows just how terrible the situation there is for her, even worse than for other people who have been accused, because she is an enslaved person and person of color, and, thus, little value is placed on her life. She was exploited as an enslaved person, then manipulated and threatened until she gave the confession Parris and Putnam demanded. Next, she was tossed in jail and apparently left to rot there, as we never see her at the trials of even the people she accused.
At this point, she makes the kind of statements that people would have whole-heartedly believed earlier in the play—about the Devil coming for her—except now she is essentially ignored. It is absurd that she did what they wanted, and she still ended up in jail. Further, it's absurd that her statements about the Devil are now ignored when they were taken as God's truth before.