I said:
Nope, cause the thugs are not dead yet.
You are giving him a choice to save them, extinguishing the fire.

This can bring to interesting situations:
let's suppose the BBG is escaping with the MCGuffin and the main purpose of the thugs is to let him put a safe distance between the wizard and him (and the not-so-secondary purpose to end the PC's miserable life).

Do the character choose to run after the BBG and to be a LawBreaker or to save the thugs and his soul, but giving the BBG an advantage?

But in the situation where the character has only one refresh it isn't a choice, that's what I'm saying.  A compel should ALWAYS be a choice (saving of course those situations where the character is without Fate chips).  When you're giving the player the choice of 'Save the thugs or become an NPC' what you're really doing is railroading them into saving the thugs.

Ok, let's start this one.
First of all, Player chose that Aspect, so he was expecting that some building could catch fire.
Then Player chose to put himself in situation which could bring in a Compel and to accept the Compel itself (unless of course he was short on FPs).

The building is on fire for his character's fault, it's up to the character to put remedy to the situation. He can just use a water spell to extinguish the fire and call the firefighters and taking some Stress for the spell.
It's not railroading, it's a situation based on player's choices. And probably a situation in which the player would like to be: repairing his mistakes and making his life harder because of his faults.
(and if the McGuffin is really important this can award a second FP to the character).

Moreover, if you put a band of thugs in front of a 1-refresh wizard, you are already forcing him to not use lethal magic. Why don't spice up things?