As Dusk Falls

To earn this achievement you need Big Sam to be shot by Tyler after he enters the motel.

To accomplish this, load up the "Holts Stormed the Motel" section of the Chapter 1 story tree.

The important decisions which will impact this achievement are as follows:

When asked by the Holts who you're with, choose "Just my dad".
When Big Sam enters and Vince looks at the earring on the ground, choose to hide the evidence.
When asked by Big Sam who you're with, once again choose "Just my dad".
When your wife walks into the motel, select the option "Let's get out of here".

In the resulting scene, Big Sam will be shot and you'll earn your achievement.

A video of this achievement can be found in the video below, starting at 0:00.

Tell Tyler Vince is only with his dad.
Hide evidence.
Tell Sam that Vince is only whit his dad.
Tell Michelle Let's get out of here.

For a Full and Fast Achievements Guide check the link below:


Timestamps:

00:00 Intro + Useful Information
02:02 Chapter 1: Story
03:49 Chapter 1: Code Breaker + Smooth Criminal Achievements
05:14 Chapter 1: Message Received + Tables Turned + And So It Begins… Achievements
06:32 Chapter 1: Bungled Achievement
07:16 Chapter 1: Cop Out + Point Blank Achievements
08:18 Chapter 2: What’s Your Emergency? Achievement
09:12 Chapter 2: Story
10:08 Chapter 2: Paging Dr. Walker Achievement
10:57 Chapter 2: Keeping The Faith + Second Chance + Lifesaver Achievements
11:56 Chapter 2: Dodged A Bullet + Caught in a Trap Achievements
12:21 Chapter 2: What’s Done is Done + Unforgiveable Achievements
13:32 Chapter 3: Long Arm of the Law
14:01 Chapter 3: Story
14:24 Chapter 3: Resurrection Achievement
14:48 Chapter 3: Take Me Instead + New Dawn + From Dusk ‘til Dawn Achievements
15:59 Chapter 3: Better the Devil You Know Achievement
16:23 Chapter 3: Buried Alive Achievement
16:44 Chapter 3: She’s Coming with Us Achievement
17:18 Chapter 4: Invincible Achievement
17:49 Chapter 4: Story
18:46 Chapter 4: Cabin? What Cabin? + Brothers in Arms + Into The Woods Achievements
19:46 Chapter 4: Trail of Breadcrumbs + Once a Holt + Hands in the Air + No Going Back Achievement
21:19 Chapter 5: Bullseye Achievement
22:04 Chapter 5: Plead the 5th Achievement
22:28 Chapter 5: Story
22:54 Chapter 5: Jailbird Achievement
23:23 Chapter 5: Heart to Heart + Bonnie and Clyde + Runaways Achievements
24:14 Chapter 5: Cuba Libre Achievement
24:58 Chapter 6: Story (Wait for the Cop)
25:43 Chapter 6: Into the Wild + Breaking Bread + Past, Tense + End of the Road? Achievements
26:56 Chapter 6: Almost Made It + Enough is Enough + Stay of Execution
27:47 Chapter 6: You’re On Your Own (Chapter5) + Free Bird + Most Wanted Achievements

Achieved by Sam the cop being shot in the motel.

Choices Made were to lie about being only with father, leave evidence, and get out of there after wife comes in.