I saw a combat example in which someone Invoked a villain's "Crushed Ribcage" consequence from across the room to make him stumble during his escape; no interaction there, either.  Ditto on invoking "Building on Fire" to make a ceiling collapse and block an exit -- I can't even imagine how you'd interact with that aspect.

There are several ways you can gain access to an aspect that is on another character or scene:

Inflict a consequence

In case of an attack, the attacker starts, and then locks the results. After that the defender rolls and locks the results. A conflict can be seen, from the “attackers” point-of-view, as an apposed roll without knowing the target number (i.e. the defense roll has not been made at the time of the attack). I would use the same way of thinking in case the player would roll against a fixed, but unknown, target number.

YS200:An attack is always rolled as a contest between the character (the attacker) and the opponent  (the defender).

YS207:Against an opponent, a maneuver is performed much like an attack—you roll an appropriate skill  against the opponent and try to beat the opponent’s defense roll.

YS193: Contests are much like simple actions, except the action is directly opposed by someone else and is easily resolved one way or another. Rather than setting a difficulty, each party rolls the appropriate skill, and the outcome is resolved as if the high roll had beaten a difficulty equal to the low roll.

Second: Conflict timming.

Lets asumme im in conflikt with NPC. We roll the dice. I used Aspect to get reroll/+2 so NPC do it too. So we can do it again and again?

Ie.
P: rolled + + - -
GM: rolled - - + +
P: I use 1 Aspect (descritpion)
GM: I use 1 Aspect (descritpion)
P: I use 2 Aspect (descritpion)
GM: I use 2 Aspect...
so on.

• a player can use the same aspect only once per roll. I emphasized because the other player(s) can use the same aspect.
• the aspect must be appropriate
• you need to have the necessary Fate Points, unless you are tagging

Once the dice are rolled, a taken out result is in the hands of the attacker.  The attacker can narrate any reasonable result he chooses.  I would argue that dropping a nuclear bomb on a city then narrating how everyone woke up with severe burns and massive headaches but unlimately recovered would not qualify as reasonable.  Likewise, setting off a force 12 flame burst attack in a crowd would not reasonably result in universal heavy tans and mild concussions.  But within reason, the attacker controls the story.

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.

Right, and in that situation you're now telling your player "Ok, so despite there not being a real rule about it I've decided to make your character an NPC because you have this aspect' (or alternatively "Ok, so now because you have this aspect give me a fate chip or your can't play your character anymore").

I think that may way is much less likely to cause your players to quit the game in a rage.