I know that there are similar questions, but I'd like to know what's the "preferred" meaning of "just" in a specific sentence in this context.
I was watching a GTA V movie, called "Meltdown". In a given scene, the protagonist's tutor turns to be his enemy; he wants to "destroy honest capitalism" and he's using a laptop to perform the action. Then he presses a key and says, with an evil laugh: "I just pressed this button and now tense music is playing" (and tense music starts to play in the movie). Later, the protagonist and his friend pursue the guy to stop his evil plans.
I tried to translate the movie for my mother, and when "I just pressed this button and now tense music is playing" showed up, I couldn't decide if it was something like "I pressed this button a few moments ago and now tense music is playing" or "I only pressed this button and look what happened, tense music is playing".
Taking in account that the movie is a spoof of Wall Street themed movies, and the context given, what's the most probable meaning? Was he trying to be ambiguous on purpose?
It may seem silly, but it's something that made me think a lot about ambiguity in English and can't get out of my mind.