When you need to use a multitool on something and you need to use more than one, you don't have to! All you need is one multitool. First, go up to the object you need to use the multitools on and use a multitool on it. Then as soon as you've started using it, open your inventory and wait for about a minute. Then, get off your inventory and you will find that you have now activated or unlocked the object by using only one multitool!