Put SetOnStage(ITEMGUID_TheHatch, 0); in the INIT section of a Story Goal, then put this in the KB section:

IF
CharacterUsedItem(_Player, ITEMGUID_Lever)
THEN
SetOnStage(ITEMGUID_TheHatch, 1);
PlayEffect(ITEMGUID_TheHatch, "RS3_FX_UI_PerceptionReveal_01");
PlaySound(ITEMGUID_TheHatch,"UI_Game_PerceptionReveal_Puzzle");

It'll make the hatch appear, and play the sound and visuals similar to if you discover a hidden dirtpile etc.