Funny thing about a strong base & a strong acid, when you put them together you get a powerful reaction which can be somewhat explosive - so that's the implied fifth panel. But then they neutralise each other and you get a fairly inert salt.
The thing that makes them highly reactive - and thus toxic - is their affinity for ionic bonds. But once those bonds form, that same affinity makes the salt stable and safe. Ammonium chloride is used in cough medicine.
I'm pretty sure Ammonia and Clorox Bleach are both alkali, also they famously mix to produce chloride gases, which aren't salt and definitely aren't innert.
Not until the fifth panel is drawn. Until the fifth panel drawn it is impossible to know whether they died or fused grotesquely into a single festering green-goopy figure who becomes a local superhero, and, overtime, earns the moniker of Toxic Avenger, thus rebooting the greatest franchise of all time.
By better you mean less chance of dying? I'm not positive on this, but I believe you'll make more chloramine gas with ammonia compared to the amount of chlorine gas you would with vinegar.
Both are very toxic and both would likely result in death.
IDK how much each combination produces, but I think it would take a lot less chlorine gas to kill someone. In this instance, however, I think you would die regardless.