Hard to say whether any pollen will get loose. It will depend on how you manage air circulation around the pollen plant. Definitely worth a try though, even if you end up with a small number of unexpected seeds, if you are careful, you should not have a big problem.
OTOH though, I keep my pollen plants small, and kill them once I have my pollen. Doing a selfing and keeping a larger plant alive long enough to mature seeds is higer risk than my setup, so your mileage may vary.
Good luck with it.