Rule 1 of good behavior in a laboratory (the kind where you give samples of this and that): when showing up, wait politely and in turn to be seen.

Rule 2: When the procedure you're being asked to prepare for makes you ill, notify the technician in charge of your tests.

Rule 3: When notification has occurred, please try to direct the vomit away from other clients waiting to be seen. This is not something they need to see graphically. If possible, avoid hitting the technician. He will thank you later. Especially if your appointment falls in the early morning hours.