[RPG] Can you take a rest during combat

There are 2 definitions of "round" in 5e. There is the definition of "round" that you quote, which is from initiative position intMax to initiative position 0 (or negative if you manage that some how).

Then there is the definition used here for readied actions. This is the same definition used in "once per round" effects such as certain powers. This definition begins at the beginning of your turn and ends at the beginning of your next turn.

Because (unlike in 4e), readying an action and activating it, doesn't move your initiative order position, and because it matches the readied action refresh timer (which happens to use the same 1/round definition of round), readied actions can be used at any point in either the current round or the next round prior to your turn.

Here's how reactions refresh:

When you take a reaction, you can’t take another one until the start of your next turn. If the reaction interrupts another creature’s turn, that creature can continue its turn right after the reaction. (Player's Basic p70)

This is a large part of the support that leads me (and many others) to believe that readied actions can roll up to your next turn.

First off, these things sometimes happen. If this is a one-off occurrence, I wouldn't be too concerned: people sometimes get it into their heads that they need to do something "weird" for no good reason. I was playing in an In Nomine game as an angel who could possess people/animals; I somehow decided that I needed a monkey, and we spent about as long planning a zoo heist (that never happened).

So, one-off: don't worry too much.

If this is a more common event, or if it looks like it might be (Tom sounds like he might encourage this kind of "weird strategy" thinking), there are a couple of things that have been helpful in my games:

1. talk to the "problem" player(s): remind them nicely (and privately) that there are other players who need to be included in the action and the planning. yes, this is the default answer to anything with the problem-players or problem-gm tags; it's the default answer for a reason.

2. remind the players that time is passing in-game. In this particular example, while Tom and Frank were discussing what to do with the interlopers, the captain could be struggling against his bonds, the captors could be rummaging around the cargo hold, a sailor could be whimpering behind a crate. As the planning session goes on, the captors might get more violent, roughing up a sailor who gets in their way. D&D does encourage some "free action" tactics talk among the players, but time does flow.

3. if they still don't get the hint, a brigand could actually accost the PCs: demanding money, ordering them around, etc.. Roll for initiative! And, remember that the brigands are totally getting a surprise round (are those still a thing in 5E? Sorry, my experience is almost all 3.5/PF). I'd encourage relaxing some of the rules about how long talking-type resolutions take (or, at least, suspend initiative if someone rolls well enough to warrant a brief cease-fire), but there comes a point where conflict is inevitable (this is a good thing: the whole point of RPGs is resolving conflict) and the PCs can't just talk amongst themselves any longer.

4. alternatively, poll the players to see if they want to continue with strategy or move into action. Tom and Frank can talk about tactics all they want, but if the cleric steps in to stop the pirates from harming their ship's captain, Tom and Frank will have to respond. This can backfire! Tom and Frank can be angered by the cleric acting "before they're ready"; therefore, I encourage mixing this in with #2: "Tom and Frank are whispering about what to do; Cleric: you see the brigands roughing up the sailor; Druid: they're dumping something unpleasant from the hold into the bay. What do you do?"

I'd personally be hesitant to actually use one, but I've seen suggestions to use a small hourglass (a 30-60 second timer) to let the players discuss how to respond to a new situation before in-game time resumes. The in-universe logic being that the PCs have been traveling together for long enough that they can quickly communicate how to respond to violence with a subtle gesture, where the players need to actually talk.

You'll have to be a little careful to not step on Tom's fun in planning intricate strategy, but that's relatively easy: make sure that there are plenty of encounters where the PCs know what's coming far enough ahead that they can talk for a few minutes in-game before the enemies know they're there.