Did Angel sell out the others to the Mallers?

Scratch talks to Angel after the tower fell and not only calms angel down but lays down the reality of his situation and asks where did they go. He responds with FU
everyone assumes this is non co-operation. However scratch gets mad and the heart machine starts going nuts.

Is the spelling of the base “Irwin” or “Urwin” because if you wanted to say “eff you” wouldn’t it be “FY”
Assuming the prisoners are using a system similar to the tap chart that prisoners use in real life. Where you will make a series of taps down and across chart to a corresponding letter, however you will select first letter of word in that system. If the base is spelt “Urwin” the Mallers wouldn’t be aware of the base and thought Angel was giving them the finger when he actually was co-operating because he wanted to survive.

Thoughts anyone?