How do I optimize my Region3 player detection?

I'm trying to make a mock auto duels for practice, as the applicability of using Region3s extends far beyond that scope. The issue I'm having is that the system has troubles detecting the player's character, and, probably more consistently, detecting when the character leaves the region.

Server Script:

local Players = game:GetService("Players")
--------------------------------------
local Arena = workspace.Arena
local Room = Arena.Room
local Spawns = Arena.Spawns
local Pads = Arena.Pads
local StatusBoard = Arena.StatusBoard
--------------------------------------
local Regions = {}

for i,v in pairs(Pads.Team1Pads:GetChildren()) do
	local SelectedPad = v
	Regions[i] = {Pad = v,Area = Region3.new(SelectedPad.Position,Vector3.new(SelectedPad.Position.X,SelectedPad.Position.Y + 12.9,SelectedPad.Position.Z))}
end

for i,v in pairs(Pads.Team2Pads:GetChildren()) do
	local SelectedPad = v
	Regions[i + 3] = {Pad = v,Area = Region3.new(SelectedPad.Position,Vector3.new(SelectedPad.Position.X,SelectedPad.Position.Y + 12.9,SelectedPad.Position.Z))}
end

while true do
	wait(.1)
	for i,v in pairs(Regions) do
		local Parts = workspace:FindPartsInRegion3(v.Area,Pads,math.huge)
		for _,Part in pairs(Parts) do
			local Character = Players:GetPlayerFromCharacter(Part.Parent) 
			if Character then
				v.Pad.BrickColor = BrickColor.new("Really red")
			else
				v.Pad.BrickColor = BrickColor.new("Medium stone grey")
			end
		end
	end
end

As I mentioned, the above code does work. It simply doesn't work well, and I'm unsure of what else I can do to optimize it. Any help would be greatly appreciated.

Edited Code

local Players = game:GetService("Players")
--------------------------------------
local Arena = workspace.Arena
local Room = Arena.Room
local Spawns = Arena.Spawns
local Pads = Arena.Pads
local StatusBoard = Arena.StatusBoard
--------------------------------------
local Regions = {}
local PlayerRoots = {}

Players.PlayerAdded:Connect(function(Player)
	Player.CharacterAdded:Connect(function(Character)
		local Root = Character:WaitForChild("HumanoidRootPart")
		if not PlayerRoots[Root] then
			table.insert(PlayerRoots,Root)
		end
	end)
	Player.CharacterRemoving:Connect(function(Character)
		local Root = Character:WaitForChild("HumanoidRootPart")
		for i,v in pairs(PlayerRoots) do
			if v == Root then
				table.remove(PlayerRoots,i)
			end
		end
	end)
end)

for i,v in pairs(Pads.Team1Pads:GetChildren()) do
	local SelectedPad = v
	Regions[i] = {Pad = v,Area = Region3.new(SelectedPad.Position,Vector3.new(SelectedPad.Position.X,SelectedPad.Position.Y + 12.9,SelectedPad.Position.Z))}
end

for i,v in pairs(Pads.Team2Pads:GetChildren()) do
	local SelectedPad = v
	Regions[i + 3] = {Pad = v,Area = Region3.new(SelectedPad.Position,Vector3.new(SelectedPad.Position.X,SelectedPad.Position.Y + 12.9,SelectedPad.Position.Z))}
end

while true do
	wait(.1)
	for i,v in pairs(Regions) do
		local Parts = workspace:FindPartsInRegion3WithWhiteList(v.Area,PlayerRoots,math.huge)
		if #Parts == 0 and v.Pad.BrickColor == BrickColor.new("Really red") then
			v.Pad.BrickColor = BrickColor.new("Medium stone grey")
		end
		for _,Part in pairs(Parts) do
			local Player = Players:GetPlayerFromCharacter(Part.Parent) 
			if Player then
				v.Pad.BrickColor = BrickColor.new("Really red")
			else
				v.Pad.BrickColor = BrickColor.new("Medium stone grey")
			end
		end
	end
end