Can you tell me if a person took a whole container of rat poison could that kill them?

Depends: What kind of rat poison? And, no one should do that to begin with.

Very worrisome: If you are having thoughts about killing yourself, get seen at the nearest emergency room now. Have a friend or relative drive you or call 911 for emergency services for transport. You can call the National suicide hotlines 24/7 at 1-800-suicide (1-800-784-2433) or 1-800-273 – talk (1-800-273-8255) for support.