I don't think interrogating her further is going to do anything if she isn't able to elaborate on this sensation.
I think I also will place a little bit more stock in this info, since Ran's the first person to say something about the sensation happening. We couldn't have deduced that some people felt something when this happened because it had yet to come up, and we've talked to at least one person that was both awake the entire time and smart enough to think to give us any info they had (Nazrin) who didn't say anything. Why Ran felt this and Nazrin apparently didn't is curious enough on its own.
Also worth noting is that Ran is telling us this individually and is not saying anything about anyone else claiming to feel it. She's been here the whole time and we've clearly demonstrated that we're, at the very least, well acquainted with Byakuren. This strongly suggests Byakuren didn't feel this sensation, because surely she would have said something and Ran would have pointed this out to us since we arrived late. (It's a good bet Ichirin didn't feel it either, given what she's said.)
Beyond that, it gives us something new about which to ask, and depending who gives us yes or no answers we can narrow down who may be more or less helpful or possibly even draw a correlation between those affected and those not. That Ran got this sensation when none of our friends apparently did is quite bizarre, and actually gives me even stronger feelings about heading to Eientei so we can check on another topside animal youkai. There's also the big and obvious option of asking people on the mountain, with the Moriya Shrine given special attention since Kanako is demonstrably Perceptive Of And Good With Bizarre Things.
