Is The Hepatitis-B Immune Globulin Safe?

My son is doing a paramedic program and he was told that if he had his 3 hep b vaccinations (which he has) that he didn't need a hep b serology test. He began his program in Jan and was since told that he does need the test. He had it and his level was below 3.1. He is under a time constraint because he has his hospital practicum on Feb 11 and needs proof of immunity in order to participate. He is getting a booster today and is going to get another hep b serology test done in 2 weeks. Is there a chance his immunity levels could come up to 10 in two weeks? Also is the Hep b immune globulin safe? (As a short term option to cover him so he can do his hospital practicum. Thanks for any advice on this!