You need to read back through the history of this forum. Many people have Gallstones and many are using the flush to try and get rid of them. For the flush to work well it requires you to abstain from drink and food for a few hours to help build up and store bile, just like you would do before an ultrasound for the gallbladder or other organs. This will interrupt your use of supplements but the next day you can certainly continue using them. To use them on the flush afternoon/evening is probably pointless anyway as you will be literally flushing everything out. It's up to you. Have a break from food/water and pills and do a flush Have food/water and pills, do a flush and not have good results and possibly also modify your after affects.
Look up the Hulda Clark e protocol that is on this site to see how it works.
During the flush you cannot rupture your gallbladder the worst that can happen is a gallstone may get stuck in the bile duct but this may happen with or without a flush and is what causes gallbladder pain attacks in people. If a stone does get stuck, the usual approach given on this site is to relieve the pain with some more Epsom Salts and to do another flush as soon as possible.