When Darryl goes to get the door and come back to the entrance of the living-room, we see a shot of Prue's camera and a coffee table, then he's attacked by the Gremlocks and he fall to the ground breaking the coffee table; well if you play this part on slow motion you'll see the coffee table it's already broken before Darryl hit it.
It's possible that they used a stunt-prop table. This is where they pre-cut the legs from a table so that it will break easier when an actor or stuntperson falls on it.
Hey, the table might not even have broken if he fell on it so they had to make it break, it TV and so this isn't a big deal because you watched it in slow motion, so then it wasn't obvious in the real show, so it wasn't a slip-up because you wouldn't even have known.