(The previous chapter's error has been rectified. I put the chap on a timer but inkstone uploaded the same chapter twice for some reason. Third time his happening T_T.)
He didn't just stop at turning the customers into Sleeper Cells though. But, he also planted Blood Vitality Grass in each, using healing as a pretext. That's why it took him a couple of minutes to heal their limbs.
Otherwise, with his attributes growing stronger, it could be done even faster.
The Blood Vitality Grass in them was only like a seed that hadn't germinated. If it just grew in size, it would alert them as their bodies would be growing stronger too, not to mention the greater sense of hunger they would be feeling.
But, as they were in the Folkan Secret Realm, they would of course come across many opportunities to grow strong. That means, as long as the Blood Vitality Grass grew every time they grew in strength, none would be wiser.
