discuss how dimmesdale's behavior on the scaffold reveals his psychological stress?

This is sort of Dimmesdale's dry run at public confession. He has lived with Chillingworth for quite some time now so his stress is showing. He's sweating, sickly and semi-dillusional. Hester and Pearl, who are returning from Governor Winthrop's deathbed, mount the scaffold, and the three of them stand hand-in-hand. As he speaks, a strange light in the sky illuminates the scaffold and its surroundings. Looking up, Dimmesdale seems to see in the sky a dull red light in the shape of an immense letter A. THen He sees Chillingworth smiling at him. Dimmesdale has another panic attack but hey, it's a step in the right direction!

The first thing that comes to mind is his constant pain in his chest, but his delirium after seeing Reverend Wilson is also interesting because he is so obsessed with both getting caught that he even fantasizes about the entire town seeing him with Hester and Pearl.