A&E is the only place, I believe, that will not fault you for barging in to get immediate attention for your requests. (Unless, of course, your request are trivial and not emergencies) Otherwise, the professional healthcare staff will surely attend to your need and do their utmost to ensure your requests are met satisfactorily.
On the other hand, you do not barge into your client’s office demanding to meet them without an appointment, you do not barge into a meeting you were not scheduled for, you do not enter the toilet if there is someone inside and have not given you permission, etc …
It bewilders me that people can have the obtuseness to disregard such basic courtesy, by coming into my office to request for an immediate meeting without pre-scheduling. Even ignoring the fact that I was in another discussion, and requested to meet in 5 mins instead. (Guess people don’t get it here) Eventually, I had to say I will find them when I am available.
Don’t take other people’s time for-granted, schedule a meeting before hand and keep to the time.