A combat encounter began with both sides noticing each other from a very long distance. The players planned readied actions or reactions for the approach of the enemy.
Player 1, a heavily-armored fighter/cleric, stood in front to give cover to the back rank but readied a 5 ft move diagonally to the back and left in reaction to the creature entering any space in a 10 ft radius to his front. This would prevent him from giving cover to the enemy.
Player 2, a fighter with Polearm Master and Sentinel feats, performed a Dodge action since he expected to perform an attack of opportunity when the enemies approached. His attack would include a trip, which could make the enemy prone and impose disadvantage on any ranged attacks.
Player 3, a fighter/rogue striker, prepared to throw a dagger at the closest enemy within 20 feet when Player 1 moved. He would use Lucky to gain advantage and thus get sneak attack.
The sequence of reactions was:
- A creature entered Player 1's trigger area, making him pull back and give the others a clear shot.
- Player 1's movement triggered Player 3's attack, making him attack the creature with advantage and sneak attack.
- The creature continued to advance, triggering an attack of opportunity from Player 2 which tripped the enemy and knocked them prone.
The order of these reactions is very convenient for the players. If Player 2 had attacked before Player 3, the enemy would have been prone and not suffered sneak attack damage.
What are the rules that help you adjudicate the order of actions/movement/reactions in this kind of combat sequence?
I think the issue is rooted on setting ready action triggers on a given position along a creature's movement, instead of a starting or finishing point, since that creates a sort of "bullet time" effect. Suddenly everyone is taking reactions and the creature is effectively time-stopped in the middle of what's supposed to be a constant, simultaneous movement flow.