In the course of an answer to this question about ways to gain advantage on death saving throws, the following was proposed to gain advantage on a death saving throw:
Alternatively, you could be a Wild Magic Sorcerer, and use Tides of Chaos.
Starting at 1st level, you can manipulate the forces of chance and chaos to gain advantage on one attack roll, ability check, or saving throw. (PHB p. 103)
The problem to resolve:
Being at 0 hit points includes the condition unconscious. The condition unconscious includes the condition incapacitated. Being subject to those two conditions means that the Wild Magic Sorcerer has the following constraints to overcome in order to apply Wild Magic's Tides of Chaos to his death saving throw.
Unconscious (Appendix A p. 292, attack vulnerability not germane to this Q)
- An unconscious creature is incapacitated (see the condition), can’t move or speak, and is unaware of its surroundings.
- The creature drops whatever it’s holding and falls prone.
- The creature automatically fails Strength and Dexterity saving throws.
Incapacitated (Appendix A p. 291)
- An incapacitated creature can’t take actions or reactions.
Is using the Tides of Chaos an action, a reaction, or is it something else?
Magic is a part of every sorcerer, suffusing body, mind and spirit with a latent power that waits to be tapped. (PHB p. 99)
Tides of Chaos is a "once per long rest" ability. Because it is Wild Magic, which is a bit unpredictable, and because it is a bit "meta-gamey" in that its function is to changes die rolls, and because a Sorcerer's magic is something inherent to the Sorcerer ...
Does Tides of Chaos' characteristic as a class feature get around the problem of being unable to act for an unconscious/incapacitated character (who wants to use it to get advantage for a death saving throw) or does being the character being unconscious trump all of that?
1 Options for action being described in "Your Turn" (Basic Rules p. 69-70)