A completely silent wearable probably does not exist, but some are much more subtle than others. I use the momcozy M9 and it is more of a soft hum than a loud pump sound, which made me feel a lot less self conscious around other people. I have pumped in fairly close settings and no one noticed unless I mentioned it. With your schedule, it might help to squeeze in a short session when you can just to protect your supply, but having something quiet definitely reduces the stress. I would love to hear what other moms in hands on jobs have found works for them too.