Oleoresin capsicum is a pepper OIL.
Probably wise to wipe down any other contact surfaces with disposable wipes.
When I owned a Pizzeria in a PA college town years ago, just about every semester some d-bag decided it would be funny to let some go inside the place late at night when we were packed with drunk students.
Because we never knew where ground zero was, cleanup was as usual, and we never experienced any secondary contaminations due to any residual product.
One thing I can say based on at least half a dozen incidents, is that once airborne, the suspended particles are very light and stay suspended in the air for a good amount of time as opposed to quickly settling around the immediate discharge area, so the affected area may be large, but that may be a good thing because it's concentration may have diminished enough in a large open area like a theater to not be a serious hazard.
Still risky of course, so be sure insulate yourself from being liable for any future occurrences due to any residue, because it would be foolish to make any guarantees or promise 100 percent removal of something so widespread.