In verse 30, we learn of a third group of people who were not ashamed. They were the only ones who managed to stay at the tree and continue to partake of the fruit. What did they do that was different from the others? "They did press their way forward, continually holding fast to the rod of iron." They did not let go of the rod. I suppose that they were moving along by putting one hand over the other, not letting go for a minute—continually holding to the rod.
Moreover, when they finally made it to the tree, these people fell down. Why? Out of gratitude. That’s why. They actually fell down before they had even eaten the fruit. And so, there may be several other reasons why someone in this situation would fall down. They could be humbling themselves. "To fall down" in the ancient world meant literally "to bow down." When someone came into the presence of a powerful person, he would prostrate himself on the ground in front of greatness. You see this in the Egyptian depictions of a person entering into the presence of pharaoh or one of the gods. In bowing down, the person did not just bow his head; he bowed his whole body and fell to the ground.
In the Beatitudes, when it says "blessed are the poor in spirit," the phrasing can be understood as saying, "blessed are they who bow down themselves to the earth." They are brought down and humbled. Maybe the people reaching the tree fell down for reasons of paying tribute or giving honor. Maybe they fell down out of exhaustion. They had completed a hard, long journey. Perhaps, they were overwhelmed by the entire experience at the tree and fell down for that reason.
Whatever the reason, their gratitude and humility made them different from the others who simply partook and then wandered off. These were the people who did not let it affect them when they looked around and saw other people mocking, ridiculing and scorning them. They did not pay any attention to the comments of other people in the great and spacious building. They had their testimonies. They were firm. And they were grateful to God.
Book of Mormon Central, "Why Did the People Fall Down at the Feet of Jesus? (3 Nephi 11:17)," KnoWhy 202 (October 5, 2016).
"Thus by falling to the ground, those who worshiped Christ at Bountiful ritually signified that their bodies were created from the dust of the earth, that they were mortal and fallen, and that they were willingly humbling themselves in the presence of their Creator."