When a NY cop visits his estranged wife at her LA office building, he stumbles into a terrorist heist and must rescue the employee hostages.

"When terrorist take over his wife's office building. A shoe less NY Cop must outsmart the bad guys and free his wife from their clutches."?

Pretty good, does the job.

As usual, a trade off has to be made in information for the sake of brevity. ?Here's my trade off:

When his estranged wife becomes a hostage in multi-million dollar heist, a wise guy cop must foil ruthless robbers and rescue the hostages.
(23 words)

That's what I see as the hook. ?As far as bait:

Estranged: ?He's got to rescue her in spite of conflicted feelings; this implies the subjective, relationship problem that needs to be rectified in the course of achieving the objective goal.
Multi-million dollar: ?to underscore the monetary stakes. ?It's not a nickle-and-dime job.
Wise guy: A defining characteristic but not a character flaw. ?He's in sufficient jeopardy without the need to be handicapped by a character flaw. ?His character flaw is in relation to his relationship with his wife -- not his performance as a cop.
Ruthless:?To underscore what kind of villains he's fighting, the amplitude of his jeopardy and that of the stake characters, his wife ?and the other hostages.
Foil and rescue: ?One dramatic problem with 2 stakes: ?money and lives.

fwiw