[@Duthguy]

Whether Thokk takes damage or not depends on his armor class. Since Thokk has and armor class of 16 enemies need to roll at least a 16 to hit him. The two troglodytes attacking Thokk each attacked three times. Out of those six attacks, only three managed to roll a 16. These three attacks dealt a combined damage of 14 hit points.

As for the miasma, Thokk's fighting the trogs at the temple right? That's a good 20 feet away from the dead trog, meaning you're 10 feet out of the miasma's range. So I wouldn't worry about it.