It was a difficult choice.
Forcing their way through would mean declaring war on Snow Ninja Village.
She could, of course, gamble that Naruto wouldn't do that.
After all, according to the "unspoken rules of the Shinobi World"...
The Shadow of every ninja village was supposed to be the very picture of "levelheadedness." The successive Raikage might have seemed increasingly hot-tempered and simple-minded, but in reality, every Raikage had thought carefully before making any decision. That included starting or joining the first three Shinobi World Wars. A few years ago, they had even tried to kidnap Hinata Hyuga by force during peace talks, then threatened to start a war with Konoha over the death of their peace envoy. Every one of those decisions had been made as part of an overall strategy.
The Fourth Raikage was, after all, a seasoned Shadow who had seen his share of battles.
In other words...
If the Shadow of any other village had appeared before Tsunade at that moment, she wouldn't have felt so troubled, because they were "reasonable." But the one before her now was Naruto, a boy of only fifteen. He had set a new record as the youngest person in the Shinobi World to become a Shadow. Even Naruto's father and the former Third Hokage had been over twenty when they took office. By a ninja's standards, that wasn't "young."
At the very least, they could be called "adults."
But Naruto was, without question, still a boy.
And given the way he'd acted in the past...
Who knew whether Naruto might choose the most extreme course of action without regard for the consequences?
Defecting from Konoha.
Going to war with the Mist Ninja.
Taking the two Tailed Beasts that had originally belonged to Kirigakure.
And now he'd even mastered Sage Mode.