Alma sees; the servants see; the lady servant of the queen, Abish, sees; all because of direct manifestations from the Holy Spirit based on correct understanding of eternal truth.
Verse 14 says that Ammon saw that the Spirit of the Lord poured out upon the Lamanites according to his prayers. It was in the seeing and the discerning of the significance of that outpouring of the Lord's Spirit upon the Lamanites, a group of people that had been the source of so much contention and conflict among his own people, that Ammon felt a profound sense of gratitude towards God for what was being done. So great was the joy that he now felt that it overpowered his physical body, just as had happened to the king and the queen moments before.
This leaves the servants of the king and queen, who upon seeing these three leaders overpowered with the Spirit also begin to pray because the fear of the Lord had come upon them. This causes them all to fall to the earth. Everyone in the king's house is now lying on the ground except for Abish, who we learn has already been converted to the Lord without making it known.
When Abish sees what has happened, and understanding the cause of it, she sees an opportunity to bless the community around her as well. By inviting the people to come to the house of the king to see the king, queen, Ammon, and all the king's servants overpowered by the Spirit, Abish is hopeful that this "would cause them to believe in the power of God," (verse 17).
What resulted however was confusion, and instead of just saying that there arose a great contention among the people because of what they saw, the scripture account takes pains to articulate seven different conclusions that the people came up with to explain the scenario in front of them. None of them had a correct knowledge of the actual events that had transpired. None of them had the perspective of eternal truths, and thus they devised many different reasons as to why they found the king and his household laying prostrate upon the ground.
Finally, Abish returns and having found the whole of the gathering in a confused uproar of contention, she immediately goes to the queen. The queen and king arise and begin to express testimonies of conviction and of having their hearts turned to the Lord, which things the multitude had no understanding of.
There is a parallel between this story and doctrines of the Apostasy and the Restoration. Men, when left to their own devices, are not equipped to understand the things of God. In the dark grays of this world, we grope for understanding and explanations of why things are. However, the knowledge that comes from God, like shafts of illuminating light, help us to understand correctly our very natures and the purpose of our existence.
The people that gather to the king's house, came without gospel light, and seeking for explanations they devised many probable causes, but none of them were the truth. So it was with the Great Apostasy which proceeded the Restoration. Many tried to reform the church of their day based upon what they were reading, but none had direct revelation from God to do so.