The pills were nothing more than a stamina-boosting panacea that is commonly used by mercenaries during any hunt.
Closer to poison than actual medicine, excessive consumption would harm one's body on a biological level as it messes with one's sense of hunger, while regularly pumping the user with enough endorphins and adrenaline to keep them awake and run without pause for long intervals, while it slowly dissolved in their stomach.
Hence the mercenaries only used it in rare cases when there was no other option left and considering that they had to be ahead of the Knight and their target to set up an ambush, they had to use any advantages they could get.
Before doing that, Kareem still had to confirm the location the two were aiming toward. And as the two kept moving, he knew where they were going. It was easy to guess from the head movements of the Knight and their target. "Confirmed target, drink water. We will be moving toward those twin mountains."
