My character died am I wrong to be frustrated?

[MaxWilson]

Were I in the DM's shoes, I would have had the bandit captain barter for his life, holding a knife to the neck of their downed comrade, forcing the players to make a decision. The captain backs out slowly (I would actually act this out with my own body as I go into the adjoining room), while the character's player rolls the death saving throws every six seconds, and the players are left to make a choice...

This only works if you change the 5E rules on death saves. You can't ready a multiattack, so by strict 5E rules, this tactic is just an invitation for a PC to let you make your attack (-2 death saves) and then cast Healing Word to completely negate your attack AND get the PC back up to positive HP all in one bonus action. The threat is therefore ineffective, under vanilla PHB rules.

But if you change the death rules to something like "each failed death save costs you 20% of your HP, rounded up, and you die when you reach -100% of your max HP; a successful death save or receiving magical healing stabilizes you" then this threat can be effective to some extent since you're threatening an auto-crit and Healing Word will heal far less damage than your auto-crit will inflict. Even better if you also rewrite the rules for readied actions so that Multiattack still works.

Both of these changes are good ideas for their own sake already, but the fact that they allow hostage-taking in this scenario is a nice bonus.

Probably what I expect most people to do: Realize attacking right now might be suicide and plot their revenge for later when the situation is more favourable/profitable.

Part of the problem here seems to be a mismatch between backstory (a gladiator who's already fought his way to the top) and reality (he's still a first-level PC).