PHB 197 for the crit part on death saves
Don’t worry, Yotta Zo was downed by the second attack so only the last attack hit him while he was down = 2 failed saves
You need to watch it again, this is exactly what happened. He’s got two out three failed death saves going into next episode.
That stuff Mearls is working on (cost of success) seems like something out of Burning Wheel, or Award Winning Table-Top Role-Playing Game Dungeon World ™. In both cases the players state their intent (deal damage, seize _______ (position, item, etc.), create an opening for escape, etc.) and the dice tells their level of success. Really good rolls will give them what they want with no strings (or give them more of what they want, like hold), middling rolls give them it with a complication, and poor rolls often mean they fail to get what they want and a larger complication arises.
In this case, they wanted to resolve things amicably with the temple and leave on the moon bridge. I would say they either got what they wanted completely, or with the small complication that they needed to leave that night (instead of having the option to stay another day if they wanted). A greater complication may have required them to secure donations to the temple (like a sponsorship from Yotta’s parents), led to the loss of some temple guards in exchange for a loss of player resources (HP, spell slots, etc.), the loss of the moon bridge as a travel option, or whatever Adam could think of. A failure could be a combination of those previous things without the PCs getting any kind of forgiveness, or they could have lost the moon temple (ie. bloodbath) and had the other temples of the arcana pursuing them (moon is mysterious and surely has ways of getting information around), or it could have suddenly become mara party time/undead invasion. It is amazing how a little bit of dark power can fix that level-gap problem.
D&D obviously didn’t help them with the situation mechanically, but I’m happy with how they resolved it. Especially since it serves as a reminder of how life has different value in this world.
Ah, so it is, I missed the part where Zeke accidentally lowered his HP from an attack that didn’t hit him, which he fixed up, my bad!