To be fair to Tyler, while he hadn't told Michael how bad his supposed PTSD had gotten, he did the right thing - consulting a doctor and telling said doctor all he knew about his state. And he got the correct diagnosis. That his inner Voq would then take over and kill the doctor was not something Tyler could have foreseen Happening. Anyway, while we the audience know Michael seeing a red angel wasn't a signal of mental instability, Michael has no way of knowing that, and after the events of last episode, guessing that there is a non-supernatural connection to the mysterious signals makes sense, so it's really good she came clean to Pike. As Lorca would have said, context is for kings. :)