Hm, weird, I couldn't see the video, just a kind of link, so no clue what this dude was doing.
I dunno. I treat my colonies using the same vapourizer unit that Danno does. When the colonies are vapourized, all the open spaces are sealed up tight as a button. Barely can even any vapour be seen coming out of the colony. That colony is left sealed for 10 minutes. There are no visible vapours, I do not worry about inhalation of them. I always wear a good quality gas mask anyways. My vapour unit is hooked up to long cables that are attached to the battery, they are about 20 feet long and I stand a longs ways off. There is no way on this good green earth that any fumes could even come close to me. Oh yes, and by the way, I wouldn't do it on a windy day. I would with a tiny wind, but I would stand up wind. Don't know what all the panic is about vapourizing with oxalic acid. It is quick, efficient and kills mites. Period. Anyways, just my two cents here. Have that beautiful, most great day, with that best health. Cindi