You're only calling that once, right?
Since it runs repeatedly, you'd only need once.
GetAll is a heavy lookup, especially on the server every half second.
You "might" squeeze some more time out of it by not using GetAll, and instead have a table updated when players join/quit/die/spawn whatever, but, that would only be me guessing, and, runs risk of missing some error condition.
(Imagine old badly written prop protects... "This item belongs to ..." and "..." left hours ago)
Even with that, you're looping a table, a somewhat costly endeavor.
My experience level really doesn't know much more to offer.