UltSans' mind is way chaotic, more than any Sans version, including Dust, Horror when his hungry gets into him, or even Insanity. UltSans has way too many stuff over him, as:
- Used to be Dust at some point in his past
- ADHD
- C-PTSD
- Chronic Depression
- Chronic Anxiety or worse (no idea because I don't the levels)
- ¿Autism? (Not confirmed, but probably generated, or inherited but was different? I don't know about this, so... That's why is between question marks)
- Post-Schizophrenia (Can have at any time, as already did in the past)
And... I don't what else. So yeah, when he panics, all of that random amount of words that seems to not make sense, is because of all of this. Are more like multiple voices or multiple himself, asking himself and then also answering himself. That's why he seems to answer himself, and how he also answer non made questions as are anticipated answers.
This also applies to the Canon UltSans versions that are known and mentioned as Raziel instead of UltSans. With some differences, but slightly so is better to assume what they actually have instead of trying to perfection what I'm unsure or don't even know.