NPC dialogue script, for loop not working properly?

I have a dialogue script that allows the player to press E on an NPC and start a conversation. Pressing X makes the dialogue progress to the next sentence, and Z exits the conversation.

I have a for loop that's supposed to loop through each sentence that the NPC says, and output each letter, one by one. It's having issues though. For some reason, after exiting the conversation, it tries to output the very first sentence, even though the player has exited the conversation. Another problem I noticed, is that the dialogue lines will be in the wrong order sometimes when you re-initiate the conversation with the NPC.

I'd appreciate any help with the above two problems.

Here's a video of the script in action, and the bugs I mentioned: https://www.youtube.com/watch?v=30WUfX3blEQ

Below is the code portion that is relevant. The for loops start around line 91 and goes to line 119 in the UserInputService function.

--// Services
local RunService = game:GetService("RunService")
local UIS = game:GetService("UserInputService")
local Players = game:GetService("Players")


--// Main Variables
local DetectedNPC = nil
local Detected = false
local Chatting = false
local Next = false
local Exit = false


--// Player
local Player = Players.LocalPlayer
local Camera = game.Workspace.CurrentCamera

local Gui = script.Parent
local Sounds = Gui.Sounds
local PromptLabel = Gui.PromptLabel
local LineLabel = Gui.LineLabel


--// Character
local Character = Player.Character or Player.CharacterAdded:Wait()
local CharHMR = Character:WaitForChild("HumanoidRootPart")

--// NPC
local NPCS = game.Workspace:WaitForChild("NPCS")


--// Functions
UIS.InputBegan:Connect(function(Input)
	if Input.KeyCode == Enum.KeyCode.X then
		if Chatting == true then
			Next = true
			Sounds.Click:Play()
		end
	end
end)

UIS.InputBegan:Connect(function(Input)
	if Input.KeyCode == Enum.KeyCode.Z then
		if Chatting == true then
			Exit = true
			Sounds.Click:Play()
		end
	end
end)

UIS.InputBegan:Connect(function(Input)
	if Input.KeyCode == Enum.KeyCode.E then
		print("E pressed")
			
		if Detected == true  then
			local Lines = DetectedNPC:FindFirstChild("Lines")
			
			local npcName = DetectedNPC.Name 
			LineLabel.npcname.Text = npcName --Displays NPC's name in dialogue GUI
			
			local npcImage = DetectedNPC.NPCImage.ImageLabel.Image --NPC's image that will be displayed
			LineLabel.ImageLabel.Image = npcImage
			LineLabel.ImageLabel.Visible = true
			
			if Lines then
				Sounds.Click:Play()
				
				Chatting = true
				Detected = false
				
				LineLabel.Text = " "
				
				PromptLabel:TweenSize(UDim2.new(0, 0, 0, 0), "Out", "Linear", 0.2)
				LineLabel:TweenPosition(UDim2.new(0, 0, 0.75, 0), "In", "Linear", 0.2)
				
				wait(0.5)
			end
			
				for i, Line in pairs(Lines:GetChildren()) do  --DON'T FORGET TO REMOVE TEST PRINTS
					

					local Text1 = Lines.Line1.Value --Line1 StringValue

					local Text2 = Lines.Line2.Value	--Line2 StringValue

					local Text3 = Lines.Line3.Value --Line3 StringValue

					local sentenceArray = {Text1,Text2,Text3}
					
					for j = 1, #sentenceArray do
						print("lines: " .. #sentenceArray)
					
						for i = 1, #sentenceArray[j] do	--
							LineLabel.Text = string.sub(sentenceArray[j], 1, i)
							print(LineLabel.Text)
							Sounds.Talk:Play()
						
						
							if Next == true then
								Next = false
								LineLabel.Text = sentenceArray[j]
								break
							end
						
							if Exit == true then
								LineLabel.ImageLabel.Visible = false
								break
							end
							wait(0.07)
						end									
						
						if Exit == true then	--Pause & wait
							Exit = false
							break
						end
						repeat wait() until Next == true or Exit == true
						Next = false
					end
			
					Exit = false
					Next = false
					LineLabel.ImageLabel.Visible = false
				
					PromptLabel:TweenSize(UDim2.new(0, 0, 0, 0), "Out", "Linear", 0.2)
					LineLabel:TweenPosition(UDim2.new(0, 0, 1.2, 0), "Out", "Linear", 0.2)
				
					wait(0.5)
				
					Chatting = false
					Detected = false
				
				end
		end
	end
end)

This forum aint that good at finding people to actually answer the questions... you have like 121 views but no answers...