Who is Barsabas Justus Platypus and how did he not die?

According to Luke, Joseph Barsabbas called Justus was a candidate to take Judas’ place in the ranks of the twelve (Acts 1.23).  According to the Acts of Paul, Barsabas Justus Platypus is a servant in Nero’s household.  The daughters of Philip told Papias that Barsabas Justus had once taken poison and survived (apud Eusebius, h.e. 3.39).  In my Cambridge doctoral dissertation (1996), p. 52, I criticized Dennis MacDonald’s book Legend and the Apostle (1983); MacDonald wrote:

Poison was reserved for Roman officials or soldiers accused of treason.  I suggest that the story told by the daughters of Philip was not about the Barsabas Justus in Acts [Eusebius’ opinion] but about another man with the same name who according to the Acts of Paul, was in fact a Roman soldier who was saved from execution.

MacDonald offered no evidence that soldiers accused of treason would die by poisoning, or even that poison was reserved for such purposes in Antiquity.  Indeed, I’ve found that there are many texts supporting poison as a means of murdering people–the common story of putting poison secretly in a person’s food or drink.  The standard means of executing a Roman soldier was  fustuarium, death by beating or stoning by fellow soldiers.  One interesting means of Roman soldier execution was death by elephant; Alison Futrell (The Roman Games, 8) cites Valerius Maximus 2.7.13-14:

For the Younger Africanus … threw foreign deserters to wild beasts as part of spectacle [sic] he offered to the people.  And Lucius Paul [snip] … for the same fault (desertion) threw men under elephants to be trampled.

Now this is indeed interesting and perhaps you, dear reader, would permit me to suggest a solution.  Barsabas Justus was as MacDonald suggests a Roman soldier, but since poisoning was not a means a executing soliders–I’ve yet to find a single text to support such a notion–perhaps Barsabas Justus Platypus was sentenced to die by elephant trampling and yet like Thecla in Iconium, or Paul in Ephesus, he managed to escape this martyrdom. My suggestion has the advantage over MacDonald’s in that there is support from at least one text that says that Romans actually used elephants, unlike poisoning, to execute Roman soldiers!