Ideally, it should also be tagged out, so that no one else electrically energizes the instrument when you are for example gone to lunch or working on a higher priority problem. Most of the chemical problems have been addressed. Sometimes there are combination problems. These types of operations are best accomplished in a fume hood if possible. Also the addition of more people to the cleanroom roster creates potentially more problems.
Peripheral vision is limited and can pose a significant risk in a crowded environment.