I littery want a plot twist when we meet lance again we just say "remember the flower" and then beat the crap out of lance 🤑🤑🤑
Ngl, that would be Karma for him. But I could see the mc stopping Axel or Rose from beating him to the brink, saying something along the lines of "I think he has had enough, despite what he did killing him wouldn't heal the wounds he inflicted" or something along those lines. Their main concern is with Resoom anyway, so taking out Lance would be a waste of their time and energy.
But I digress, i agree that Lance needs to face the consequences of his actions, and his side of the story is gearing up to that, as i see it personally.