Wow, that was over two years ago!! It went fine. I had to be very careful about my break time. Here's what I did:
2 "long" breaks of 20 min each - pump for 15min, snack while pumping, pee. I brought a hands-free pumping bra so I could eat and drink while pumping.
Between each block I took a 5min break to stretch my legs, pee, and have a drink of water so I wouldn't be distracted during the blocks. I also hand expressed a teeny bit of milk during my 5-min breaks to minimize engorgement.
Overall, it really wasn't as bad as I thought it was going to be.
That being said, I was also about 4-5 months postpartum when I took the test. In the first few weeks after my milk came in I had a terrible time with engorgement and plugged ducts - I never would have been able to go that long between pumping sessions at that point.
I'm planning a post about breastfeeding in medical school on my blog, doctorssurvivingmedicine.com - if you check by in a few weeks, it should be up.
I love my dog and my chickens. They are much less demanding than professors or patients.