Ran Xueyi's attempt to hide him was of course ridiculous and unreasonable. She even wondered why she was doing this when she could have easily exposed everything. But because of the sudden appearance of Song Yu Han being thrusted into their lives after three years of separation made things a bit rushed.
Initially, Ran Xueyi wanted to take things slowly and let the father and son bond together. But with them being so overly possessive over her, she was afraid that either will become territorial that they would even view each other as rivals.
As funny and absurd that notion was, Ran Xueyi knew better that this would end with another two rivals facing each other in the battlefield with her being the prize at the end.
However, Ran Xueyi's plans that worked so well to others seemed to not have any effect when it comes to her son.