Run the check before you ask for questions
'Any questions?' asks someone to volunteer that they are behind. A checkpoint that everyone answers turns not-knowing into a number on the wall, and the questions follow it on their own.
Keep wrong answers anonymous
In training people are required to attend, a visible leaderboard teaches them to guess safely rather than answer honestly. Show the counts, talk about the option people picked, and leave it there.
Let the wrong answers set your agenda
If eleven people chose 'start a new one', you now know exactly which screen to go back to and why. Rebuild that part of the session rather than repeating it louder.
Ask the same question of the next onboarding group
A step that trips one cohort is a bad slide. A step that trips four is a bad step, and that is a finding for whoever owns the process, not for the trainer.
Re-run one check before people leave
Repeat the question the room got wrong in the middle. Watching the count move is the only evidence you will get that the correction landed, and it takes thirty seconds.