A better preceptor would have explained that stroke response time is kept track of and published and also factors in to the hospital's ability to be stroke certified and be a stroke receiving center. For example, a patient needs to be called a code stroke within a certain amount of time, get a CT in x amt of time, and start TPA within a specified time from the ER door to injection.
Given that you have only been there four weeks, I would be peeved that you didnt come get me straight away or get someone to double check because even if you're NIH certified, I wouldn't necessarily trust it. I worked in a neuro ICU and now I work in a mixed medical surgical ICU and you'd be surprised how completely different one person's NIH score compared to the other (for the same patient).
It's not something you lose a license over but it's something to learn a lesson over. Make sure you are familiar with the policies of your facility, like how soon should a patient who could potentially be a code stroke be seen by the ER MD. They also follow MI to cath lab response time closely as well so you may want to check that out. There are also some key sepsis core measures that need to be followed too (like BCx in ER, ABX started in ER after cultures sent.)
Good luck to you.