Stressed - BF at work hassles

I thought all was going swimmingly well with the pumping at work thing. All the surgeons seemed to be supportive, none of the nurses complained. Until yesterday when I went to the other hospital site, and had one nurse exclaim "You can't bring that in here, no fluids are allowed in the OR!". I told her that I could do it sitting away from the patient and the surgical field, and that if it made her feel better, I could dump the pump bottle contents into the storage container outside the OR. There was some muttering on the far side of the room between two of the nurses, and when I came back from getting some IV fluids a little while later, one apologized to me for seeming like she was coming down hard on me. But I had to understand that it wasn't really allowed.
Fast forward to this afternoon when the department chief suddenly wants to speak with me at the end of the day. He's received an email from the director of medical affairs, because I can't do this in the OR any more. They claim they're worried about infection control and patient safety, because I might not be paying attention to the patients. Last time I checked, breast milk was sterile, and besides, I have alcohol hand wash at my work station and wash up before and after touching anything to do with the pump. And I still perform my work in exactly the same manner as I would have if I weren't pumping.
I ended up calling the medical affairs lady to say I needed to talk about this. Why did this suddenly become an issue after 8 weeks back at work? She claims that they have pumping rooms over on labour and delivery at my hospital that I can use. I had to say that that didn't sound like it would work, since I have to pump 3 times a day to be able to feed my daughter (given my poor supply, I pump every 2 hours), and there was no way that I could leave the OR for that length of time to go pump. Even if I had 20 min between cases, that wouldn't be long enough (I need about 25 min each time probably). I also don't feel like I can stop the flow in the OR by saying that I need to take a longer break in between. Some rooms have such quick turnover that you only have 5-10min between cases. I also have some days where I have a 4h case in the morning and a 3.5h case in the afternoon. Having a colleague give me a break wouldn't work either, because that would be dependent on one of them having a long enough break in between cases to relieve me to go do this.
I was in tears during the phone conversation with her, which I had while sitting in the OR doctor's lounge at the end of the day. One of the general surgeons and one of the oral surgeons were near me during the conversation, and were outraged when I explained what was going on to them. They said there's no problem at all infection control or otherwise with me pumping in the OR. And they'd be happy to write letters to the hospital on my behalf, or to sign a petition that they'd suggest all the docs and nurses in the OR should sign.
I'll be very interested to see how this plays out. I did tell them that I should be able to continue providing breast milk for my baby, and that I didn't think I should be financially disadvantaged by needing to do so, nor should the surgeons have their lists affected by my needs. This woman seems to think there must be some solution, but I really don't see what it might be.