There are SO many possibilities, and I'm sure you must have found more than a few ideas already! Among the obvious are ...

Bringing herself to orgam while positioning herself against the (locked) door.

Stripping off and putting her clothes in the far corner then sitting at her desk for 5 minutes.

Painting pussy juice on (cleanable) surfaces within her office sufficient for collegues to notice a curious smell.

Bottomless when she interviews (behind her desk).

Using office paperclips to adorn her nips for a time, then giving those same ones to a co-worker.

Permission needed to use the bathroom (e.g. by phone), denied until it's nearly too late.

Place a picture of something like a penis behind her door for a day (nobody should see it unless they close the door, of course).

Every 1/2 hour or so giving herself a spank with hand or implement loud enough for others to hear and wonder what the noise was. (She wouldn't have heard it herself, of course, if asked).

Well ... I could continue for a time!

Hope this helps VV