That's right. Out of ~18,000 people total across 3 countries (UK, South Africa and Brazil), there have been 3 reported events requiring a pause, of which two involved people who got the real vaccine and one who got the placebo.

Keep in mind they pause anytime anything serious happens to anyone in the trial to give them time to make sure the vaccine didn't cause it. Pauses are a good thing - they are a sign they are following the protocols and not just pushing something through.