A tanker that was talking to them on VHF, telling them to manoeuvre.

If you can ignore lights increasing in intensity on a constant bearing and verbal commands via VHF, then you can ignore the radar and AIS proximity alarms (which both operated as expected).

Unless the computer is running the show, there's no way to overcome confirmation bias with beeps and flashes. I've seen it first-hand many times in training helmsmen. Sometimes in-person verbal commands are not enough, and physical control must be obtained.

It's simply a training and experience deficit. There's no substitute for time at sea or time under instruction.