My opinions are often not welcomed by the general population. So take it with a grain of salt.
Having been in a mental hospital once by choice, once forced there, & once ran from the police to avoid going back I can say with confidence that if you don't want to go back don't talk about suicide. It doesn't matter how much it bothers you. 99.9% of Ts out there don't know how to treat people that have suicidal thoughts.
If you don't mind going back to a mental hospital then by all means be completely open and honest with your T.