V8: how do Jobs work with Events?

Say I have a QueueableJob which adds thousands of users to a group. What if I need to fire an event when each user is added to that group? Will each event execute in the middle of the job and will the job wait for the event logic to complete or are the job and events asynchronous, i.e. will the jobs continue on their own without waiting for the event logic to complete, and the events will simply pile up and execute in series one after another?