Portia kills herself be swallowing hot coals, according to letters that Brutus receives. Should the audience take that literally or can you come up with a more plausible explanation?

According to Plutarch's tale (from which Shakespeare received the story in the first place), Portia swallows hot coals in order to kill herself. In Shakespeare's play, however, he describes her as "swallowing fire," which seems to be as cryptic as it is gruesome. Regardless, the viciousness of the fire seems to represent the the terror of Portia's pain of separation from her husband.