Crossword Puzzle Ltrs. of stress

Clue: Ltrs. of stress

Box office ltrs. (SRO with 3 letters)
Extreme quietness in an office that leads to stress (PINDROPSYNDROME with 15 letters)
They offer support (e.g. BRAS with 4 letters)
Offers thanks, in a way (PRAYS with 5 letters)
It's across the hall from the Oval Office (ROOSEVELTROOM with 13 letters)
__ Sports Bureau, baseball's official statistician (ELIAS with 5 letters)
Legal ltrs. (ATTY with 4 letters)
YouTube offering, briefly (VID with 3 letters)
Office missive (MEMO with 4 letters)
USAF officer (MAJ with 3 letters)