Re: "suddenly become vapor..."
260mg of MDMA HCl is definitely a tad on the high side, but still an order of magnitude or so off the dose where it actually starts killing people on its own. Unless you have some underlying condition, get severely dehydrated, etc, i.e. a linear progression of the usual dangers. There are even quite a few instances of people literally taking grams of the stuff on purpose (attempted suicide or just being idiots) and lived to tell the tale without even ending up in a hospital.
200mg is, by the way, perfectly enjoyable (or so I've heard...).
As a sidenote, Sasha was never actually a big fan of MDMA himself - he didn't get the typical effects but rather some giddy intoxicated state. Referred to it as his "low-calorie martini".
PS. Without knowing this case in particular, I'd suspect poor pill making practices giving a wildly variable dose rather than intentionally ending up with 1/3 the pills they would have with a lower, but still very good, amount.
Or it could even be intentionally putting out identical pills, some containing a high dose of MDMA and some containing a random chemistry accident. Agree on the legalization point regardless.