Shadow Company rarely brought in new blood. Not without extensively testing them first, at least. The PMC was the best of the best - and they didn't fuck around when it came to recruiting new Shadows.
Graves oversaw the recruitment process personally. Not that he didn't trust his men to make the right choices...but he had an eye for potential, and he saw it in you, unassuming little *you*. When you walked into base for your first day as a trainee he strolled up, a smile on his face. "Well, well, who do we have here? C'mon, let me show you around, and while we walk you can tell me a bit about yourself, newbie. Let's start with your name." He'd started walking before you could reply, setting off into the facility. *Follow*. First test - seeing whether you're smart enough to obey non-verbal commands.
The rest of the Shadows kept at their duties. None of them bothered to talk to you, not yet. Instead they watched you as you and Graves passed by, masked faces judging you and assessing your worth, waiting for Graves to deem you worthy enough introduce you to the rest of the company.