Very rarely do you have people rushing in to surgery rooms. Despite TV dramas, most surgeries are not high risk, most surgical patients are not critically ill, and those that are tend to be pre-staffed for the risk. OR rooms are not usually locked but the surgical suite sure is. The bigger issue with the surgical suite is proper attire. ICUs are a different matter (where coincidentally I happen to be tonight). Generally all the staff you need is already on the locked side of the unit.