That would require a whole overhaul of the combat system
The game rules are literally built for turn-based.
RAW AD&D 2e is phase-based, not turn-based. I get the feeling a lot of people have an idea of what it
should be implemented like, but not what it's supposed to be like.
IE games are actually a fairly accurate implementation of AD&D 2E's combat if you squint a bit. Yes, the actions are executed in order of initiative.
But here's a problem: This makes no mention of movement. Completely abstracting it away like many drpgs do is entirely fine with the rules from what we can read, despite a lot of people on this site seemingly averse to such combat. Simultaneous decision when using a tactical grid is a problem, what if your fighter moves to attack an orc at the same time it decides to move towards your mage? Your fighter would be out of position, standing next to where the orc
used to stand, attacking the air.
Check this example from the dmg:
Does this not read a bit like baldur's gate combat?
Simultaneous decision making, DM hurrying them forward(and even warning Anne that she will lose her round if she doesn't decide soon)?
The grid-based combat issue was resolved by the supplement player's option book
Combat & Tactics, which describes how to play AD&D 2E using turn-based combat on a grid, and was used as the basis for 3e combat.
So if one were to make IE games "turn-based", the combat rules detailed within would be what you should model it upon.