Checking tubes

So after being part of a new crew at the weekend, I maybe over enthusiasticly dipped the tubes with a stick. When doing this obviously only my hand ever goes over the top of the tube and I listen to the sound of the stick hitting the bottom of the tube and 'marking' the depth on the stick.
I got told off. "Wow, that is so dangerous" the boss said to me. " how do you tell if it is safe" I asked. " well if the quickmatch is not out of the tube where we attached it then ok". As he was saying...

Checking tubes