"Monk, we're newcomers here, it's best not to stir up trouble. Go easy on your strike, don't end up killing him."
We definitely can't pull out a dragon's tendons, your dad's the emperor, he lacks nothing, let alone a belt.
Lu Bei voiced a reminder and considered it would be safer for him to personally step in.
True, Gu Zongchen was kindhearted, but he was a Mahayana Cultivator after all, to the Third Prince, it was an unfair match, if the Third Prince turned out to be all bark but no bite, he would be dead.
Or, perhaps the Third Prince was a strong contender for the next Dragon Palace Master, always in a power struggle with the first son. Presently, being poisoned by the second son, unable to use even one-tenth of his abilities, he could wink out at any moment.
Being unfamiliar with this place, the number of ways those despicable locals can make you die was unknown, it's best to be cautious.
It's different if Gu Zongchen oversteps, he can always bully.