This subject is hypothetical completely and if the season scenario involves Palandech at QB then absolutely he belongs there (this is what I anticipate happening).
If the scenario leaves Palandech only watching, however, (hypothetical, of course) then similar to how Ohio State used Braxton Miller elsewhere when another QB arrived, I'd hope UNLV would use Palendech's play-making ability on the field somehow, somewhere.
I think he's the third fastest on the team. He's here for one year only and keeping him sidelined (if that's the situation) would be a loss, imo.
As for playing safety, I agree, who knows how physical he can be or not. I do think, though, if not at QB, Palandech is capable of competing and helping in some capacity somewhere. He's just too fast not to be used in one way or another. Most likely he'll be used at QB depending on Armani's production and readiness.