How did the men in "The Pardoner's Tale" die?

In "The Pardoner's Tale," three young men, or "rioters," overhear a funeral procession and learn that a friend of theirs has just died. The three of them make a vow to find Death and kill him, saying to each other, "And we wol sleen this false traytour Deeth . . . By Goddes dignitee, er it be nyght" (lines 669–701). On their quest to kill Death, they are told that Death is sitting under a nearby tree. When they reach the tree, however, they discover instead "floryns fyne of gold ycoyned rounde" (line 770). The men are excited by the gold, but they believe that if they take the gold openly during the daytime, "men wolde seyn that we were theves stronge" (line 789). Instead of taking the gold right then, they decide that they will sit and wait until dark before removing the gold. However, in the meantime, they want some food and drink while they wait. They draw lots and send one man to the town to find some food. While the first man is gone, the other two plot together and decide that they will kill him when he returns because then the gold will just be divided by two people instead of three. The man who went to town, however, is simultaneously plotting to kill the other two because then he might "have al this tresor to myself allone" (line 841). The man who goes to town buys some poison and poisons the wine that he brings back to the two men under the tree. As planned, the two men under the tree kill the man who went to town, but then they unwittingly drink the poisoned wine that the man had brought with him, and these two men die as well.
https://sites.fas.harvard.edu/~chaucer/teachslf/pard-par.htm