This is a hypothetical question and need to ask it in case the situation arises for me.
Due to my work schedule where I must work weekends, I must attend the closest Mass to my office that starts at 8am. Most of the time it lets out right at 9am then I must be to work and set up to start work at 9:30am. It takes about 5 to 10 minutes to get to work, then another 5 to 10 minutes to set up all I need to do my daily work (I work in IT Support, inbound calls and customer email inquiries).
If Mass does not let out by 9:05am at the latest, getting out of the parking lot at the church can be a bit of a problem. Is it okay to leave after the final blessing as the final hymn starts so I get to to work on time, I do notice a few others who leave right after Communion but before final blessing & hymn.
Unfortunately, there are no Masses that start sooner than 8am that are within reasonable driving distance to my place of work and none that start at 6:30pm or later (Saturdays or Sundays) . Also, I cannot ask to start later at my job due to staffing needs to have 2 people working on Sundays right at opening time.