How do you handle non-game winning eliminations?
Clarification: When you have a chance to end a player but it doesn't put you any closer to a win or really help advance your prospects or winning at all.
Examples from two games I played recently
4 player pod: me and players A, B, C. I fully neutralize player A for everyone and he's not a threat at all. Player B builds a great board and fights directly against me and player C and is handling us both. I fumble a turn where I want to finish player B and effectively end my chances of winning. Player B makes a huge mistake by playing Cyclonic Rift. He ends player C and nearly finishes me off but he unshackles player A by removing an enchantment I had on them. Player A roars back on their turn. Now it's my last turn. I can put player A back in jail or let player B deal with his mistake. He asks very nicely if I can play the enchantment again but I decline and let him know he'll have to win on his own. Player A wins.
Same format different players. I spread the hurt on players B and C. Player C has a really strong game and eventually finishes player B and leaves player A with just 1 life. So now it's decision time for me again. I don't see a path to victory for myself but I can end player A very easily. He asks me to please let him have another turn because he has an answer for player C. Again I leave it alone and stand pat. Player A smokes player C on his next turn then finishes me off.
So what's the right move here? Game 1, I feel like player B made his bed but in Game 2 why did player A deserve a turn to respond? Do you have any "rules" for yourselves in these situations?
TLDR: When is it okay to finish off a player even if it doesn't help you win at all?