You can always leave early. You can’t always undo staying too late.

Leaving and staying are not symmetrical, and that asymmetry is the whole point. Leaving is available at any moment and costs you some awkwardness and a bit of missing out. Staying past the point where things turned can cost a lot more, and by then the decision is being made by people who are no longer thinking clearly, including you.

Decide before you go out what time you want to be home and tell one person. Keep a way of getting back that does not depend on anybody else’s plans. If the room changes character, go then, and let the awkwardness be the price.