Also many interviews are structured so there simply won't be time to finish the exercise if you're going slow.
In this interview I wasn't concerned about that. If you are looking to see if someone understands Linux by testing diagnostic skill, if they are coming up with 3-4 different failures to check for every step... They are doing their job.
Which if you are doing real diagnostics is often 100% the wrong answer.
I double check other people's work, and make sure that everything is right. Because one small misstep can result in not diagnosing an issue correctly.
Listen to what the user reports as the issue.... not the cause. Always work from the symptoms to the problem.