You absolutely, positively can not properly zero a rifle with any kind of bore sighter without shooting the gun afterwords.
Impossible. Can't be done. You can get close, as in 8x11 paper at 50 yards but not close enough for ethical hunting.
There is no option but shooting the gun.
Don't worry about spooking deer. Walk outside and listen ( if you're anywhere near country). Nobody else is concerned. They're scaring your deer already.