Hospitals are sucky places and they do treat people like kids but they do keep you safe from yourself. There is a difference between thinking about Sui and planing Sui. If all it takes is an impulse to carry out then yeah they will keep you safe. But it sounds more like you want compleat control to do what you want even if you are unsafe. It sounds manipulative on your part, and unreasonable. It doesn't work that way there has to be some give and take, if you really want help then you need to be willing to give up some control. I'm not sure you really want help at this time, not sure what it will take but I hope you decide your life is worth more than getting your way. I completely understand not trusting docs, I've walked out of more than a few places becouse I thought they were poisoning me.

Can you give them your brothers number?
As for agreeing to be honest about Sui thoughts that is reasonable request on their part, they can't help you if you refuse to be honest. You can explain your fear of being honest and why you did like hospitals so much and I'll bet they will work with you to keep you safe and not in the hospital, if you are willing to work with them.