Continuity mistake: When Paige was invisible and Cole watched the blood, there was a large pool of her blood, but in the next shot, the pool of blood was smaller. (00:36:00)
Visible crew/equipment: When the Dark Priest finds the box containing the Lazarus Demon, just as the Seer says that she can always count on him to help, the shadow of the boom mic dips into view at the top of the screen. (00:09:05)
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.