Shen Liang thought for a long time; if he informed Si Yuchen, his responsibility would be significant. If he didn't inform Si Yuchen, then Li Lu might leak what happened in Sea City.
It wasn't Shen Liang's negligence, but Shen Biran's disappearance was both timely and subtle, leaving people bewildered.
Shen Liang was caught off guard by Shen Biran's situation and could no longer find an excuse for himself.
"I'll notify you as soon as I have any news."
Shen Liang promised Li Lu that once he had any news, he would tell Li Lu immediately, putting Li Lu's mind at ease.
If Li Lu worried further, Gu Xiaonuan would find out. Li Lu mentioned that Gu Xiaonuan is currently with Si Yuchen. If Gu Xiaonuan knew, Chen would also know.
There's no way Gu Xiaonuan could continue staying abroad; once she learns about Shen Biran's disappearance, she would rush back to Sea City.
From this perspective, it was Shen Liang who saved Chen.