Someone here, when the story first broke said possibly the two assassins combined different chemicals to cause this damage. This has actually been a theory that has been floated since it happened so that was a good call; even though, we can't be sure.
Excerpted:
The Toxic Mystery behind Kim Jong-Nam's Assassination
...
"We are building speculation upon speculation" to explain what happened, said Jean-Pascal Zanders, an expert on disarmament who focuses on chemical and biological weapons.
Airport CCTV footage on February 13 shows two women approaching the 45-year-old victim and apparently rubbing his face with a cloth. He died minutes later, according to police, who found traces of VX on his face.
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- So VX wasn't deployed? -
Not so fast. Some experts have put forward a hypothesis that the killing was carried out using a binary version of VX known as VX2.
In that case, the assassins would have separately applied two chemicals to his face, using a precursor which is not severely toxic on its own but lethal once combined with sulfur. The theory would also explain why two women were used for the attack.
"The simplest explanation is that it was binary," said Matthew Meselson, a professor at Harvard University and member of the national advisory board at the U.S.-based Center for Arms Control and Non-Proliferation.
As the two chemicals combined on Kim's face to create VX, the assailants would have been unharmed while the delayed reaction would have allowed him to continue walking as shown in the CCTV footage.
It is also easier to transport VX across borders when it is broken down into two seemingly innocuous components.
Continued: http://www.naharnet.com/stories/en/227188-the-toxic-mystery-behind-kim-jong-nam-s-assassination
