I went back to work when my baby was four months old and she is seven months now and I am still breastfeeding and pumping at work. Fortunately, my unit is not super-duper chaotic and I have only missed a pumping session a few times. Basically, I come into work and have set up a pumping station in a room that no one uses. I run in there every three hours and pump. It usually takes about 5-7 minutes. I clock in and out for lunch but usually don't actually take it since I take these breaks to pump. I hold my own pager and just let the patients wait. Once or twice I have had to run out in the middle of pumping and take care of something that I couldn't let wait. Another thing I have done to help is try not to work more than one day at a time, that way my supply does not get low from pumping and missing pumping sessions.
Floating, however, has turned into a nightmare.