They are most likely to break your chain, and try to avoid patches on the edge of the field. If you don't see any patches that seem appropriate, simply reset the PokéRadar until you find one that does. The act of resetting your PokéRadar is simply manually using the PokéRadar again, and does not break your chain.
Anyways, does running from a Pokemon break the chain?
Encountering another Pokemon while in a chain will not disrupt the chain unless you catch or faint the Pokemon that is not the one you are chaining. Running away from an encounter whether it's the Pokemon you are Chaining or not will not disrupt the Chain but will not increase it either.
Add on, does closing your DS break a chain? You can save outside of battle, but closing out the game will break your chain. You can switch your lead pokemon, use items, whatever, no chain break. If you need to take a break and step away from your game, enter into another battle during your chain. Close your DS into standby mode while still in the battle.
In spite of everything, do Trainer battles break shiny chain?
There is no shiny chain in this generation. Your shiny odds are not determined by how many consecutive KOs you've gotten, they are determined by the total number of KOs (and catches) of that species over your whole play time. It's a permanent bonus.
Can overworld Pokemon be shiny?
It should be noted that Shiny Pokémon don't appear in the overworld sprites, but can once you interact with the Pokémon similar to how it's done in Pokémon Go. The chance of finding a Shiny Pokémon randomly in Sword and Shield is the same as in X and Y, 1 in 4096 or 1 in 1365.33 with the Shiny Charm.
|1%||42||About 18 minutes|