What should I do with doing Humanoid:TakeDamage() 'simultaneously'?

I have been working on a project for quite a while. I created a First Person Shooter module and added multiple bullet shots (shotguns). However, whenever I damage a zombie with the spread, it only deals damage once (15 damage). Same applies for all of the shotguns. I have printed marking places and have checked that the code still runs. But it only does one shot of damage!

Sometimes it will do the correct amount of damage and kill the zombie!

Is this a Roblox base code issue or me?

PS I tried posting on roblox dev forum but didnt verify me even after 32 mins read time -_- PPS I realized when this problem happened it made the zombie's health bar flash red?

if roundArray then
			for i = 1, #roundArray do
				print(roundArray[i][1],"|",roundArray[i][2],"|",roundArray[i][3],"|",roundArray[i][4],"|",roundArray[i][5])
				if roundArray[i][3] ~= nil then
					hit = roundArray[i][3]
					print(hit)
					if hit.Parent.Name == "Zombie" then
						enemyHum = hit.Parent:FindFirstChild("Zombie")
						
						if hit.Name == "Head" then
							damage = self.settings.damageFunc()*1.5
						else
							damage = self.settings.damageFunc()
						end
						
						print("Enemy:", enemyHum)
						enemyHum:TakeDamage(damage)
						print(damage, "\n")
						
						marker = game:GetService("ReplicatedStorage").HitMarker:Clone()
						marker:FindFirstChild("TextLabel").Text = damage
						marker.Parent = game.Players.LocalPlayer.PlayerGui
						marker.Adornee = hit
						marker.Enabled = true
						
						if hit.Name == "Head" then
							marker.TextLabel.TextColor3 = Color3.new(1, 1, 0)
						end
					end
				end
			end
		end

I managed to fix this by telling remoteEvent to do damage to the server side