You two fall 40' down into a pit filled with spikes, each on you land on a spike, but Justin lands on one that pierces him through the side, leaving a nasty wound Critical
Justin, you take 28 points of damage from the fall
Kilthan you take 9 points of damage from the fall from a spike, none from the actual fall.
Kilthan, to you it looked like you fell 20', then appeared somewhere else, maybe by teleport? You are in a dark unlit room 10'x10' with smooth walls and no door with a 20' ceiling.
However, Justin you know you both really fell 40' and there is an illusion of a floor of the pit 20' down (Which looks like a ceiling to Kilthan right now). Justin can see above your party members looking down confused on where you might be, however you cannot hear them. Call out as you may they do not hear you either.