AOG
You asked whether this was a terrorist attack.
From the evidence presented, I think not.
Firstly, Islamic extremists who have thus far been involved in terrorist atrocities are rarely drunk, y'know...because Islamic extremists don't get boozed up in the middle of the day. That a massive no-no Koran-wise.
Secondly, as far as I am aware, aerosol cans have never been high up on the list of weaponry used by terrorists. It may be a new direction they are taking, but with the easy availability of knives, I would be surprised if your average Jahidist would even consider, a large can of L'Oreal Superhold as a primary means of attack.
Lastly - if it were indeed a proper terrorist attack, the poor lad would have been killed.
Terrorists kill people.
They don't singe them, then wander off.
I hope
a) the lad in question makes a full recovery.
b) the perpetrator is caught and brought to justice
c) this story doesn't put off any other cadets from selling poppies
d) that this 'terrorist angle' is swiftly put to bed.