Can you suggest a ritual I can do to improve my chance of leaving work in time to go to the gym during my lunch hour?

Gerald F.
It depends on how much time you have on your hands, its better to make a hard and focused work before the gym.
If after the gym you are planning to go back to work you should at least organize your time to take a shower and the time bewtween going to the gym and going back.
It's also better to take deep breaths,eat well and eat well as any other routine should be, either its work or gym.
In conclusion start experimenting with what you feel comfortable with and that you know its better for you and eventually if you keep doing it, it will turn into a habit.

Elias Z.
Get on top of your work while you are there, snack and eat throughout the day or while you work so you don’t have to stop for the whole lunch break and you are energized, maximize your workout it only has to be 30 minutes or so if you are efficient and bring gym clothes and bag so you can shower and change quickly to get the workout done.