
Its less that its something the ML said, but more so what we see the MC do. From a writing perspective we follow the MCs thoughts. He is portrayed as innocent and weak,deliberately in contrast to the ML who the authority wants us to judge and question. The ML is written to be shady but moment the MC isnt conscious he somehow has a knife and almost stabbed someone. That was more of a red flag than anything the ML did. Thats a classic misdirection.

Something feels weird about the ML cause why did MC had a knife in his hands when he was supposed to be sleeping ? and in the last chapter the MC didn't know if it was a "dream" or not and if its true that means he was forced and it seems like he has memory issues cause of what happened in the first chapter and the ML is using this to do shady stuff to make him believe that he is the crazy one,( i really enjoy this BL i love how we all have differents theories ε=ε=(ノ≧∇≦)ノ )
Im scared of what ML might do next