Interrupting the turn of another character usually requires a reaction
The problem here is that the mechanical means of the game to interrupt the turn of another player are: reaction. Abandoning its concentration requires no action (and since the action and the reaction are a similar motto, no reaction is required), you must discuss with your DM the possibility (1) by default interrupt any action / event currently declared stop focusing at a given time, or (2) if you have to wait to stop it when it is your turn.
- For case 2, if, when approaching the flying creature, he sees you falling, would he not change his course to try to intercept you?
And for case 1, How does the DM determine if it has been successful before you have stopped concentrating? Dex check? Int verification? A defender of this character might claim that he dropped the shot "at the top" before he noticed and chose to stop focusing.
It may seem to a given DM that you handle the mechanics of the turn system to provide a minimum ofstop time this allows you to interrupt their turn. Talk with your DM. The only mechanical means for an instant response (reaction) does not seem to correspond to this situation.
Some special abilities, spells and situations allow you to take a
special action called reaction. A reaction is an instant response to
any trigger that may occur in your turn or on somebody
others. (Basic rules, page 73)
Since none of these periods explicitly has this provision, nor the text on concentration, interrupt the turn of another so this requires a DM decision in terms of timing.
Arguments for the interruption
Since your concentration can be broken on the turn of another character (When damage is caused to you), you can reasonably argue that losing focus on someone's turn is consistent with that because
You can end the concentration at any time (no action required).
Lino's answer is a valid decision, just like a decision that requires you to act only your turn unless you have a mechanic who allows you to interrupt
the turn of another character. If you lose your concentration then (only your turn), your action would not be consumed – you would still take any action – but you would need to wait your turn. state that you are giving up concentration.
Whose turn is it?
During a turn, each character has his turn.
The game organizes the chaos of combat into a cycle of rounds and turns. One turn is about 6 seconds in the game world. During a turn, every participant in a battle takes his turn. The order of the rounds is determined at the beginning of a battle, when everyone launches the initiative. Once everyone has played his turn, the fight continues until the next turn if neither side has defeated the other. (Basic rules, page 72)
OK, when is it someone else's turn … what's going on?
In turn, you can advance to your speed and perform an action. You decide to act first or act first. Your speed, sometimes called your walking speed, is indicated on your character sheet. The most common actions you can take are described in the "Actions in Action" section later in this chapter. Many class features and other capabilities provide additional options for your action.
As the text on concentration does not require action (small a) to drop the concentration, nor a reaction, then the analysis of this text literally supports Lino's answer: you do not use an action, so "at any time" can be interpreted as "at any time, to include when another character performs an action in only six seconds turn. "
But everything happens "at the same time" during a race
A deputy minister may also decide to declare only what you do when he is your turn. Interrupting others (even NPCs and monsters) in turn is not compatible with the fact that this is a turn-based game. Waiting for your turn is consistent with the fact that D & D 5th is a turn-based game, with the exception of the reaction you are not obliged to use, that is when you can interrupt the turn of another character.
How often will you be happy to see monsters interrupt your turn?
When you play a turn-based game, how often do you want others to
to interrupt you during your turn? And elsewhere though, as the flight
the creature approaches you and sees you fall, does not he adjust his
Of course to try to intercept you? It does not take action to see that your position is starting to change, is not it?
Talk to your deputy minister and get a decision. Hopefully, for your idea to work, the General Manager will see what Lino is doing. If not, then wait your turn and do / declare things then.