RPGMemes

This is such a weird exchange, ignoring that it absolutely didn't happen

As a DM, you're playing with your players. You and them are creating a shared story, a shared experience, together. If a player is playing in a way that hurts the shared experience, you should talk to them. Perhaps about how they can fulfil their power fantasy without removing tension from combat.

You can consider one player souring the experience for everyone else as "breaking the rules". You don't address this by "breaking the rules" yourself.

As a good DM, you absolutely can and should be tweaking your encounters so that they're a good fit, but this ain't it. This devolves into you vs power gamer and the rest of the group will be alienated or bored as a result.

Set expectations! Make sure you're all playing the same kind of game.