I can reconfirm that TCAS is not used for ACT.
Having now caught up with the second episode I would just like to add that we should bear in mind that some details (ie comm etc) have clearly been added post edit and some of the comm quite obviously doesn’t match the footage. The best example was the beeps as the gun sight was brought to bear.
Anyway, another good episode. Even pissy Chrissy managed to act all grown up.
BV