I'm currently running Curse of Strahd and due to the "horror" nature of the setting, I'd love for there to be after battle tension especially when it comes to undead and such. For example, maybe he wasn't down and out or maybe something sneaks out of the dark. However, when I'm obviously not tracking turns anymore it's clear the "danger" is over. Additionally, continuing to track turns indefinitely just seems like it'd slow the session down.

So, how can I keep player tension after combat has officially ended, but I want my players to be unsure?