Perhaps I can give a bit of insight to the macro in question.
First of all, UOA does not allow you to bypass the delay between using an item. You cannot use UOA to double click 3 explosion potions at the same time and target your adversary.
There will be a normal "You must wait to perform another action" if you try to use an item too quickly in UOA. Exactly like what happens when you dbl click an item too quickly in UO. There's an approx 1 second delay between using items (but it's lag dependent, shorter delay if you have good lag, and longer if you are laggy)
Explosion potions have a 3 second delay before it explodes. Once you double click it, you will get a targetting cursor and the 3 second timer will start. You have a couple of options at this point:
1) You can now target and throw it at your adversary immediately and hope your adversary wait in the current tile for 3 secs until the explosion potion goes off.
2) Or, you can hold it for 3 seconds, then target and throw the explosion potion. This way, your adversary doesn't have the luxury of 3 seconds to run away.
So far so good?
Now, if you hold off throwing the potion immediately, you can also press esc to cancel the target cursor. The timer will still continue to countdown. Before it reaches 3, you can double click that same potion again to bring up a target cursor and throw it normally. Hopefully, you managed to throw it at the last second, robbing your adversary the chance to run away. So basically it works like option 2 above.
During that 3 secs that you cancelled the target cursor, you can do something else, like open you spelbook, remove your helm, pick up loot from the floor etc. You can also double click another explosion potion! Which will begin it's own 3 sec countdown.
You can cancel this targetting cursor also, and do something else. Now would be a good time to double click the first explosion pot (it's still counting down remember?) to bring up a target cursor and throw it at your adversary. Once your have thrown that, don't forget the second one that's still ticking away in your backpack. Double click that again and quickly throw it like what you did for the first one.
If all goes well, your opponent would be struck by 2 explosion potions in succession.
This is approximately what the 2 potion UOA macro does.
Now, remember that the countdown is 3 seconds? It goes boom on the 4th second. Also, remember the item use delay in UO is 1 second?
If you want to cut it really close, you can do this :
1) prime potion 1, cancel, wait 1 sec (potion 1 has 3 secs left)
2) prime potion 2, cancel, wait 1 sec (potion 1 has 2 secs left, potion 2 has 3 secs left)
3) prime potion 3, cancel, wait 1 sec (potion 1 has 1 sec left, , potion 2 has 2 secs left, potion 3 has 3 secs left)
4) re-prime potion 1, throw, wait 1 sec (potion 1 is away, potion 2 has 1 sec left, potion 3 has 2 secs left)
5) re-prime potion 2, throw, wait 1 sec (potion 2 is away, potion 3 has 1 sec left)
6) re-prime potion 3, throw (potion 3 away)
With luck, your adversary will be hit by 3 potions that he/she does not have time to run away from. Once you know your adversary is using this tactic, one defense is to precast G-heal and run towards bomberman. Or find some way to break line of sight (hiding, cast/run behind a wall etc).
The potions are not activated at the same time, it doesn't really even explode at the same time. Rather, they are timed to reach your target and explode at approx 1 sec intervals. Something like how modern artillery can adjust the trajectory and propellant to allow multiple shells to hit the target at the approximately the same time.
That's what the 3 potion macro basically does. In short, UOA doesn't allow you to bypass the timer. It does however, allow you to do the above which requires impossibly steady hands and accurate mouse clicks to pull off.
