Correct me if I'm wrong, but one thing I will assume is that BK TWR is able to see local traffic on radar - there needs to be some thought given to whether they can give advisories to avoid the sad event that happened today.
Nope, they have a small LCD monitor that sits behind them and is purely used to see the flow of traffic. i.e congestion levels, amount of a/c in the training area etc...
SY radar monitors
all a/c outside the 3nm radius of BK.