Asgorath
Explorer
Let me try explaining this in a slightly different way. I've been talking about your turn as an ordered list of discrete elements. However, the part I probably should've emphasized more is that you play and resolve each element one at a time, i.e. you don't declare the full list at the start of your turn and then work through it (you can certainly declare what your intent or plan for your turn is in advance, but it has no in-game meaning). This makes questions like "am I done with my Attack action" fairly trivial to answer as you go.
1) Move. You process your movement as a discrete element. You and your DM agree where your character is now positioned.
2) Attack. You make one or more attacks against one or more targets in range. You roll to hit, DM tells you if you hit, and you roll damage if needed.
3) Move. Turns out you killed the target(s), so you move over towards some other targets and get into melee range with them.
4) Attack. You still have an attack left from Extra Attack, so you make another attack roll against the new target. DM tells you if you hit, and you roll damage if needed.
5) Move. You still have some movement left and just killed another target, so you move over to a 3rd target in preparation for your next turn.
6) Shield Master shove. At this point, there should be zero confusion about the fact your Attack action is complete, and thus the Shield Master bonus action has been triggered, and you can shove it prone for your Rogue buddy who's already standing next to it.
My underlying point is that each of these is treated as a discrete element that gets resolved independently of everything else. At no stage were you doing two things at once, each element is processed separately. Given that the round lasts roughly 6 seconds, each element has an in-game duration, but the specific duration is not really important. You assemble your turn out of these discrete elements as you go, and each element is adjudicated before moving onto the next one.
So, the question might be, what happens if you really want to shove someone and still have attacks left from Extra Attack? You have two choices:
1) Use one of your attacks to shove them, using the normal shoving rules.
2) Your Attack action is done and you shove them with your bonus action.
Given that (2) basically means you lose attacks from Extra Attack, it doesn't make much sense to use your bonus action to shove while you still have attacks from Extra Attack left, right?
1) Move. You process your movement as a discrete element. You and your DM agree where your character is now positioned.
2) Attack. You make one or more attacks against one or more targets in range. You roll to hit, DM tells you if you hit, and you roll damage if needed.
3) Move. Turns out you killed the target(s), so you move over towards some other targets and get into melee range with them.
4) Attack. You still have an attack left from Extra Attack, so you make another attack roll against the new target. DM tells you if you hit, and you roll damage if needed.
5) Move. You still have some movement left and just killed another target, so you move over to a 3rd target in preparation for your next turn.
6) Shield Master shove. At this point, there should be zero confusion about the fact your Attack action is complete, and thus the Shield Master bonus action has been triggered, and you can shove it prone for your Rogue buddy who's already standing next to it.
My underlying point is that each of these is treated as a discrete element that gets resolved independently of everything else. At no stage were you doing two things at once, each element is processed separately. Given that the round lasts roughly 6 seconds, each element has an in-game duration, but the specific duration is not really important. You assemble your turn out of these discrete elements as you go, and each element is adjudicated before moving onto the next one.
So, the question might be, what happens if you really want to shove someone and still have attacks left from Extra Attack? You have two choices:
1) Use one of your attacks to shove them, using the normal shoving rules.
2) Your Attack action is done and you shove them with your bonus action.
Given that (2) basically means you lose attacks from Extra Attack, it doesn't make much sense to use your bonus action to shove while you still have attacks from Extra Attack left, right?
