Shoot an arrow towards a player starting from location

[Hosom]

I am trying to make a skript that transforms Dispensers into automatic turrets, using arrows contained inside, when powered by redstone, they automatically shoot arrows towards players.

I can't manage to create a proper vector, i made the arrow go from the player to the dispenser but not vice versa and i can't manage to fix.

on place of dispenser:
    add event-block's location to {turrets::*}

on break of dispenser:
    remove event-block's location from {turrets::*}

command /removeturrets:
    trigger:
        delete {turrets::*}

every 1 seconds in world "world":
    loop {turrets::*}:
        loop all players in radius 20 around loop-value:
            set {_loc1} to loop-value-1
            set {_loc2} to loop-player's location
            set {_dir} to vector between {_loc1} and {_loc2}
            broadcast "%{_loc2}%"
            shoot a creeper from {_loc1} at speed 3 {_dir}

Edit: tried also this but it's not working..

every 1 seconds in world "world":
    loop {turrets::*}:
        set {_loc1} to location above loop-value
        loop all players in radius 20 around loop-value:
            set {_loc2} to loop-player's location
            broadcast "Test"
            shoot an arrow from {_loc1} at speed 1 direction from {_loc1} to {_loc2}