You are correct, however it is not quite as simple. The "safety pilot" has to be designated as PIC, and that is how he logs the time. He must also be able to legally fly as PIC. Should something go wrong, or violations get busted...this is the person the FAA will go after.
Good luck finding a school to rent a 300 to you under these conditions......it may be a violation of school policy. Also, fyi....."some", (all the ones I know), employers will not count that time when evaluating you for a job.......
It is a disaster waiting to happen......