I have to tread carefully with this question, Lost.
I am, by trade, a nurse. Here, however, I am an addict, no different than any one else. So, let me answer your question with what I know to be true in MY neck of the woods as compared to what the "medical" answer may be.
In our local ER, you will be held for 72 hours if you claim to be suicidal. You will have a psych evaluation done. You will NOT be given any medications pending that evaluation for alleviation of withdrawals. No benzos to help you sleep. No narcotics whatsoever. Therefore, you are going to go through your withdrawal in a hospital setting cold turkey as opposed to going through it at home, cold turkey.
The hospital will only treat your symptoms. For example, if your heart rate is high from withdrawal, they will give you a medication to bring that down. Again, this will do nothing to help your withdrawal. You will likely be put on oxygen. Nothing withdrawal related once again. If you are vomiting, they may give you an anti-emetic to prevent you from throwing up. However, if they suspect you are an opiate addict (and the nurses and docs are trained to see this from a MILE away) you will not receive that kind of medication because it can be addictive as well.
Basically, you are going to put yourself in a withdrawal situation under the care of doctors and nurses...but will receive little care that is directed around it. And, remember of course, that it is always possible that they may keep you longer if they feel you are a danger to yourself and others.
We have seen many addicts pass through the ER stating that they are suicidal, or they think they are having a heart attack or claiming they were just in an accident. Unfortunately for most of these people, there is little we can do for them except offer them a gurney bed in the ER, check your symptoms, do what little we are allowed to do to alleviate them and then, send you back out on the street.
Now, if you are going cold turkey at home...and develop withdrawal symptoms so severe that it feels like you are in physical crisis, by all means...go to the hospital! They WILL take care of you until you are through your crisis. Don't shy away from seeking medical attention if you truly need it. But, my suggestion is to be honest with the doctors and nurses so they can treat you properly. You aren't the first addict we've seen in the ER and you certainly won't be the last. Tell them that you are withdrawing from (whatever your drug of choice was) and that you are trying to get clean. Assure them that you are not there to receive more narcotics for pain, etc...but that you are just very uncomfortable, scared or panicked. You will get a lot more empathy from the nurses if you are honest.
I personally wouldn't go the "suicide" route. You may really not like the outcome.