scoreboard players add @s[scores={dummy_z=..-16}] dummy_z 16

execute unless score @s dummy_z matches ..-8 run function bd:control/warp/warp_to_saved_coords/z/n4
execute if score @s dummy_z matches ..-8 positioned ~ ~ ~-8 run function bd:control/warp/warp_to_saved_coords/z/n4