Lionfish do not move toward you to sting.
They will stay away from you if they know that you are the boss of the tank.
They will move to the opposite corner if you give them time to do so.
They will display as a warning.
Just be aware of where the Lionfish is as you move your hands and arms through the tank and move slowly enough to give it time to get out of the way.
If you are poked by a Lionfish or Rabbitfish, place your hand in very warm water and massage the area for as long as feels comfortable. This moves and diffuses the venom away from the point of entry. It may hurt for 2-4 hours. If an allergic reaction begins, if you start to swell up, take Benadryl and or go to the hospital.