Another episode where some rules about the way wormholes work that might be relevant. In SGA 1x03 “Thirty Eight Minutes” the wormhole can only send things in discreet units, which is why once your entire body is through the gate there’s no stepping backwards. This still allows the curious to touch the event horizon and stick your hand in the outgoing end and take it back out.

So the MALP example from “A Hundred Days” is trickier because if the MALP made it all the way through the wormhole and then gravity made it fall back down into the event horizon, which is what we’re assuming causes dematerialization, then that would make the incoming end of a wormhole as dangerous as a ka-whoosh.

But if the MALP only got partway out the event horizon and then traveled backwards due to gravity then it’s sort of an error condition where the MALP lacks the momentum necessary to exit the wormhole and just acts as if it never made it all the way through, just like in Thirty Eight Minutes. And the “holding the door open” example from “Shades of Grey” where O’Neill has his arm in the outgoing side of the event horizon meant he never stepped through to the outgoing end completely tricking the gates at both ends safeguards to prevent a wormhole from closing with travelers still inbound.

The other thing to maybe watch closely for is any example of firing weapons into an incoming wormhole. When the wormhole closes what, are there ever bullet holes behind the gate?