If there was one thing that Allen learned from being friends with Gwen and Gary, is that they don't leave no stones unturned and no questions unanswered. When he has the hint of them following him, he instantly used the cloak and used it to escape the two.
He made sure to take note that the effects of the cloak was on cooldown, so he had no means of escaping later. This was a huge setback for Allen, but it was also the quickest and best way to hide from the two.
In the dark alleyway where he agreed to meet with Jeremy, he positioned himself in the darkness. He stood by the wall as he observed the waves of people walking by.
"It must be nice to be normal," Allen said to himself. All throughout his life, he was always the odd one out.
When he was a mute and he had white hair, he was an outcast. Now he was normal, he had a big secret that would ultimately turn his world upside down, making him still an outcast.