why check down by 5000?

Code:

---

void player_gravity()
{
	int z_offset = 0;
	var z_check[2]; //vector
	
	vec_set(z_check, my.x);
	z_check[2] -= 1; //check down by 1.
	
	z_offset = c_trace(my,z_check,IGNORE_ME + IGNORE_PASSABLE + ACTIVATE_SONAR + USE_BOX);
	
	if (0 == z_offset) { //nothing was hit. we are at least 1+ above land
		//let gravity kick in....
		Move_Force[2] -= iGravity * 2 * time_step; //must be odd number ?	na nm.
		player_state = ps_drop;	
	} else {	
		
		//we must of landed ;) //recover to jump... BUGGY
		if (Move_Force[2] < 0) { //ok we dropping.
			if (Move_Force[2] < -20) { //down force.... no more then 20, we can keep falling if on next check :>
				player_health += 0.80 * Move_Force[2];
				if (player_health < 0) {
					player_health = 0;
				}
			}
			animatejump = 0;
			Move_Force[2] = 0;
			iRecoverJump = 8; //impossible to recover lol.
			player_state = ps_drop;
		//	Move_Force[2] = 0;
		}
		
		if (iRecoverJump > 0) {
			iRecoverJump -= 1;
		}
	}
	
	return 0;
}

---

heres what im using now, and it works perfect. no problems as of yet...