An Chuxue's X-ray vision, although not possessing any offensive capabilities, has been growing in range and distance as she began her cultivation.
When Han Jing had just followed Han Qingjue to the underground palace, she stayed in the front hall of Beihan Palace and meticulously examined the entire Beihan Palace, not leaving a single corner unchecked. Unless there was a very strong barrier blocking her sight, it was impossible for her not to see clearly. And in the entire Beihan Palace, besides the underground palace having a barrier, there were no other places with barriers that she couldn't see through.
After Han Jing and others entered the underground palace, she was given some time, yet she did not discover anything unusual.
