It's quite reasonable to ask about such things. At least now you know what you needed to know.
On the other hand, the risk of getting stung by a lionfish you're trying to kill or stash in a container is not inconsequential, and if you're under 25 dives, how much experience do you have being task-loaded (e.g.: camera or other gear requiring attention)?
I would think exposure to lionfish when hunting would be a matter of degree, which I'll represent progressively here:
1.) Spear it, somehow get it off the spear, let it drop, and if it's wounded just let it be.
2.) Spear it, but then try to 'put it out of its misery' with a knife.
3.) 1.) or 1.) & 2.), plus try to stash it in some sort of container to remove for eating later.
If you're concerned about eating them, I assume you plan to collect the bodies somehow & haul them out. More task-loading.
If all that combined doesn't bother you, let me risk a little fear-mongering. In some areas some animals have learned divers sometimes offer handouts of slain lionfish; groupers, moray eels and even sharks. I don't know how at ease you are with predators yet, but if a reef shark, large moray or barracuda takes an active, close interest in you, are you ready for that?
Before you start carrying around freshly speared, bloody, maybe even thrashing a little, fish.
Richard.
