Most of the movie was done handheld, and for the most part, the camera being not so perfect is what we wanted, but in some shots (standing up to view the office & the reveal of him in the white room) we wanted more static shots because in the film they are both pivotal moments, and the shake ruins the tension that's built up to those points.
In other cases the shake is okay, like in one scene we have a three and a half minute tracking shot around the entire office, and if it was 100% steady it would have seemed robotic.
Think while it's still legal.