I've experienced something similar years ago. I wasn't scared of the dome/bubble/underground place. I was having a more extreme reaction prior to being placed in the dome. I was flailing about, crying and apologizing to the universe for being. Shouting / mumbling "I'm so sorry everyone. Please forgive me." The apologies were to everyone for my selfish ideations and the thought that I'd throw away my gift. I was dealing with some things in my life, and I had some really bad ideas about how to solve my problems. A few moments after being shown why I'm here, in tears, I began the aforemention apologetics and thrashing.
I was placed into the dome with an entity shortly after or maybe even to cut off the wailing. It felt like a womb or protective place and I relaxed. Entity never spoke, it merely observed. After some forced meditation together, I came back and I was fine. Shook up, but feeling catharsis.
Sorry if the report is confusing. It's even more of a blur to me now than it was then. I have no idea what any of this means objectively, Or how much of it is still accurate in my mind. I do know how the whole thing felt, and I wouldn't hit the "undo button" if I was ever handed one.
I hope this helps, I don't have much in the way of advice. It seems like your experience was a wonderful one, and I hope your takeaways are positive like mine were.