Sharla could never kill. If it wasn't for Seth, she wouldn't be where she is now— murdering, completing contracts, living a life she never asked for. Right there's the word that defines everything.
There's the entire purpose of House. They're one mob among many in the city, killing for cash. No matter how reluctant Sharla is to admit it, the truth is plain to see. Batton accepts contract after contract as the family completes them with flying colors. Everyone in House tackles them readily, with the exception of one man, Donovan; he refuses, the only member with the will to push against the slope House is sliding down with every wad of bloodied bills. The only one with a spine.
Sharla hadn't even been strong enough to refuse her contract last month. To take out Andy. Seth had fired the bullet, of course, but the weight is on both of them… and she can feel herself spiraling down, down, down. She, Batton, and all the rest of House are falling.
No matter what, one fact is undeniable: House does well. House does better than any other like it in its underground line of work.