I agree wholeheartedly with the Publishers Weekly review above about this suspenseful, "if flawed," book. The hook is supposedly 4 Wall St. trapped in an elevator under the guise of an escape room team-building exercise, but the book focuses on new hire Sara Hall and the soul-draining life of 100-hour work weeks devoted solely to making money.
The book was suspenseful enough to keep me reading, but the characters are shallow, the writing's only so-so, and it's filled with unexplained plot holes, twists that aren't remotely believable, and tons of out-of-nowhere action compressed into the last 50 pages ("Quick - wrap it up! We don't want it longer than 350 pages!").
All in all, a disappointment. There are lots of better thrillers out there, like Thirteen and The Chain.