Howard arrived in the training room with Waxel and Harkel before he began explaining what truthfully happened when he met the Ancient one.
He told about the Ancient One's intent that he sensed, and how he even reached the top of that mountain. He specifically told them how thanks to his Emperor's Ki, he was probably able to get beyond the wall at the top of the mountain.
This was probably also the reason why even the Demon King Earl wasn't able to advance his Ki Hearts to the next level. He didn't have the same type of Emperor's Ki that Howard did, so he was never able to breach the barrier the ancient one had in place. Because of that, Howard was in a unique position! It was no wonder that he was able to develop his Ki Hearts!