How can female patients stay safe?

Some facilities do give a choice whether to be in an all female or male/female area. They should all have that choice, I think.

But then with so many transgender folks these days, how do you maintain sex-segregated areas now? Inventory their body parts when they are admitted? Or what?

If an elderly "male resident in a facility were to force his way through a locked door" he'd be quite a Hercules. Such a person, if they exist, needs psychiatric intervention to help determine appropriate medication.

This is a topic to bring up with the administration at the facility you work at. I take it it's not an issue or either the place would be shut down or youd be aware of strict protocols already in place.

If these are typical problems at your facility they need to be reported, whether anonymously or not, to your local regulating authorities.
You should also go to administration with others seeing what you are to ask after protocol. Who to call in emergency. Staffing concerns if there are some.
You can also reach out to ombudsman for your facility.

In my opinion, a man this aggressive should be in a Psychiatric facility. They need to be Medicaided and not released until the right medication is found.

I don't care if they have Dementia or not, no one should be able to harass or touch another resident in any way. That goes both ways. Women can get aggressive too. We have had discussions before about men and women together in facilities. I have to agree that they should be kept in separate wings. How do women protect themselves, its very hard. But, I blame the facility for allowing these aggressive men to remain.