Well it may not particularly look like interrupting anything, but it feels that way. Sinclair walks up to the sight of Jack crouched over his father's dead body and wonders briefly if he ought to go back downstairs and wait a while longer, but the sound of the door sliding open has probably already alerted Jack to his presence.

It smells something terrible in here, but after the room with the decaying Big Daddy, it's nothing he can't tolerate.

Sinclair gently clears his throat.

"Waiting room's got nothing."