Why are there so many "horror stories" and people saying not to get versed during a procedure? isn't it supposed to be a safe drug?

Versed alone : Is a very safe drug, when you add with narcotics it is still safe but breathing needs to be monitored. Versed is safer than propofol.

Sedative: Versed(Midazolam) is a Benzodiazepine which is routinely used for sedation during surgical procedures. It helps alleviate anxiety and provides some form of amnesia. As with every kind of drug, it does have its "negative" effects like respiratory depression but if used in the correct context under direct supervision of a physician there is usually minimal side effects.