Yeah, I really recommend not doing this. When you are in that altered state you may feel you are covering your use well but believe me, it is dead obvious to everyone. It may feel like you have waited a couple of hours to go back and redose but it has only been about 25 minutes, and then you return more talkative or with more pep to your step. Sorry but not much of a way to use a bullet in a crowded kitchen without going to the bathroom.
I worked in kitchens for a few years and it was always completely obvious who was going to the bathroom every 30 minutes and doing coke. At the best, you will quickly become ostracized at work. At worst someone may even call the cops and you could be taken out of your restaurant in handcuffs (not many good places to ditch a bullet in a restaurant). Not super likely, but keep in mind that the middle ground of this scenario is being fired. And kitchen staff talk to other kitchen staff. You could quickly get a reputation that may make it harder for you to work. We had a few "coke head kitchen staff" in our town that every restaurant knew not to hire.
I agree with Troy. If you are moving to using an addictive drug at work, particularly if you feel you "need it" to make it through your shift, your problem with the substance is likely escalating.