This is an Easter Egg which only works if you attempt to block the NPC's (Non-playable Character) way which ensues them to say things you normally wouldn't expect them to. However, this doesn't work on everyone. It will only work on Bartholomew, who is Bentley's little brother, and the female pandas from the Bamboo Terrace. Though, trying to block the pandas' way is much tougher than doing the same to Bartholomew. I discovered this Easter Egg by accident when I thought that Bartholomew is following me. It's definitely worth giving this a try for a laugh.
Also, this Easter Egg will only occur if you start the whole game from scratch on a new file. When you're at the beginning of Bentley's Outpost for instance, walk towards Bartholomew and talk to him. He asks you to break the boulder which is blocking the doorway. When you destroy it, proceed to the next area but don't walk through the doorway entirely. Turn around and you should see him standing on one of the steps behind you. Go over and talk to him and he'll tell you to move out of his way since he is supposed to be moving ahead of you.