Hello, Please note I am not Yuttadhammo Bhikku but just trying to help answer your question to the best of my ability.
If you are practicing vipassana according to the Satipatthana Burmese style of Mahasi Sayadaw, then you are noticing the breath at the abdomen, specifically the rising and falling motions. When the belly rises you would note "rising" and when it falls you would note "falling". The awareness is focused on the knowing of the sensations of rising and falling such as pressure, tingling, contraction, heat, coolness, etc. Whatever sensations and characteristics you notice in that specific area that make up a "rising" movement, moment by moment, as just as it is happening.
If another predominant object arises in awareness, such as pain in the shoulder, or hearing, then you would gently bring the mind to the predominant object and start to note that. For any predominant object of awareness based on hearing, smelling, tasting, touching, seeing and thinking. The mental labelling helps to create a clear perception and clear knowing of the object as it is, not me, not mine, and not "I am" (ie. not part of a "self"), just an impartial object in awareness that is present and not good or bad (not to be judged).
If you are noticing that the mind is starting to separate from the body and the predominant object is fear, then you would start noting "fear, fear, fear" and focus awareness on the fear itself, without judging it or attaching / clinging to it. Just observing the fear as an impartial, detached observer, as it is. The fear is there as the object and then there is the mind as a watcher, observer of that fear
However, if the fear gets too intense, I believe it is acceptable to gently bring the attention back to the sitting posture (touch points) or the rising/falling of the abdomen. This can help to ground you and bring the mind back to stability in physical, tangible sensations, rather than getting caught in abstractions.
Perhaps this Q&A would also help; specifically the question at 41:40 "Whenever I am mindful of my breath, noting rising and falling, I keep controlling my breath. Any advice on how I can fix this?" Here is the link: https://www.youtube.com/watch?v=HZ7PvwbN6g8
Best of luck to you