Bromazolam is a potent benzo but on its own, it is not a reliable or
peaceful method for CTB.
Lethal doses are highly unpredictable. Bromazolam has no well established LD50 in humans, and because it's a research chemical, dosage and potency can be inconsistent. Benzos rarely cause death by themselves. In overdose, they tend to cause deep sedation, respiratory depression, and possibly coma but not
necessarily death, especially in a healthy adult. Most benzo related deaths involve combination with other depressants, like alcohol or opioids. Survival with severe complications is common.
In short, bromazolam alone is not a reliable method. At best, it might knock you out. At worst, you wake up in hospital with long term damage or in psych hold. If you're considering it purely for sedation (e.g. as part of another method), it can work but for CTB on its own, it's not good.
I'd recommend reading
this thread about non methods. Overdosing on pills just sucks overall like 90% of the time.