On Fri, 16 May 2014 15:25:35 -0500, John S wrote:

Well, as soon as (or maybe before) the water in the towel
evaporates/boils/steams, it will become impossible to survive.

It seems, from the references, that 90 seconds is the golden
time period you need to get *out* of the burning aircraft.

So, all it has to do is stay wet for a few minutes to do
the intended job of helping to dissolve HCN gases.