"Gastro breath test, lack of patient engagement"

Recently went to GRI for a gastro breath test and it wasn't a pleasant experience.   I felt barked at by a nurse who did not introduce themsleves, nor did they explain what the test would involve or work to put me at ease. They also did not check any personal details other than my name which was given to them by the receptionist.
   I was rudely told "blow here" and then they placed the straw I had used on their desk, told me to swallow a tablet with water and took me to a room where I was left on my own to wait. They did not explain why I was waiting or how long I would need to wait for, or what to do if I needed help/bathroom etc. The nurse then collected me and proceeded to use the same straw that they had placed on their messy desk (unsanitary) into the tube and asked me to blow in once again. No information was given on the timescale for test results.
Whilst I appreciate these tests are fairly straightforward I would have expected the nurse to have a engaged with a welcoming approach and to explain what was involved in a pleasant manner without prompting.