Lap button cancelling workout?

I was starting a workout (a run, as part of a Garmin Coach programme I am part way through) and pressed the lap button accidentally, immediately after starting. It seemed to remove the workout from my watch and I just had to do a 'normal' run. 

I'm always nervous of pressing the lap button in a workout because it might be to start the next section or it might be to finish a section I'm on prematurely.

Is there a way to cancel the 'lap button press' and go back a step?

(it doesn't help that trying to read the small writing on the screen for instructions isn't that easy)

For info, this was the workout:

SPEED REPEATS