Doctor starts to fly across the universe, lamenting poor service (5)
I believe the answer is:
fault
'poor service' is the definition.
'fault' can be an answer for 'service' (I have seen 'bad service' mean 'fault' so perhaps 'service' could also mean 'fault'). I'm not certain of the 'poor' bit.
'doctor starts to fly across the universe lamenting' is the wordplay.
'doctor' indicates an anagram.
'starts to' says to take the initial letters.
The first letters of 'fly across the universe lamenting' is 'fatul'.
'fatul' anagrammed gives 'FAULT'.
Can you help me to learn more?
(Other definitions for fault that I've seen before include "Shortcoming" , "Sin, error" , "Defect or imperfection" , "Flaw - defect" , "Defect or offence" .)