Wizkids Rules!

So if the non active player wants to use a global which makes the active player decides he wants to use a global at the same time, so therefor the active players global takes efefect priority, is the non-active player locked into the global he wanted to use initially?

This situation shouldn't really arise.

Consider this situation in a game between Sydney and Josh.

It is Sydney's turn. She's just rolled many dice, and during her Main Step intends to take a number of actions. She sees Josh has dice in his Reserve Pool, and there are a few Global Abilities he might want to use.
Sydney begins taking actions (such as purchasing dice, fielding characters, and using Global Abilities). Josh wants to use some Global Abilities during Sydney's Main Step but needs to wait until she's done with all of her actions.
Sydney completes all of her actions. Josh uses a Global Ability, and resolves it completely. Sydney now has the opportunity to take more (consecutive) actions before Josh can use Global Abilities again.

In a scenario where the non-active player used a Global Ability (one that would deal damage) and the active player used a Global Ability to prevent that damage, the game would not rewind past the first Global.

-The Dice Masters Rules Team