You’ve got an intruder in the house—maybe more than one. It’s night, and you don’t know where they are. You’re the only one in the house who can fight, meaning you can’t rely on a partner. Outside of a few Jason Bourne movies, you’ve never seen how a fight unfolds in close quarters. Now you have to clear your home and stop the bad guy before he hurts someone you love.

What do you do?

1) Stay Defensive

If at all possible, let the bad guy come to you rather than vice versa. This is possible if you and your family are all in the same room, or if you can set yourself up between them and the bad guy.

If he has to come to you, he’ll have to enter your line of fire. You can pick a spot with a good vantage point—for instance, along the side wall of a room the bad guy has to enter—and wait for him. When he enters, you’ll have a split-second advantage where you see him and he hasn’t yet seen you.

That said, sometimes you don’t have the luxury of staying in one place. Maybe your kids are in another part of the house, and you need to reach them before the home invader does. In that case, it’s important to go on offense the right way.

2) Moving

You always want to move purposefully. In a potential fight, that means moving—potentially under fire—with a purpose. You need to get from X to Y safely, as quickly as you deem necessary.

When you’re moving, take shorter than normal steps and keep your knees slightly bent. This keeps you well balanced and lets you move quietly. Moving quietly can be crucial—the last thing you want to do is alert the bad guy to your location, especially since he’ll have no qualms shooting through walls to hit you.

Using a ‘heel-to-toe' step—lift your foot slightly higher than normal for your step, place your heel down, and then roll your foot forward until your entire foot is down and your weight is on your forward foot—can also help you to be quiet and balanced while you move.

3) Clearing Hallways

The most dangerous circumstance in a fight is when someone can see you, but you haven’t seen them yet. So when you enter a new area, you need to ‘clear’ it: do a quick visual search to identify any assailants or confirm that the area is (for now) clear.

This is easy in a corridor, when you’re confronted with two walls and can see what’s between them. It becomes harder when you’re trying to enter a room or a T-shaped hallway (where the hallway branches off to either side), so let’s go through those scenarios:

Entering a hallway: When you’re entering a T-shaped hallway, you need to clear the area to either side. But if you just go in guns blazing to one side, you’ll expose your back to an area where your assailant could easily be. So instead, look past the near corner and move slowly forward, clearing progressively more area as you move. This is called “slicing the pie”, because you slice the uncleared space into smaller and smaller pieces.