To add on to DrJokepu, while trains depart frequently it can take quite a long time to get from the middle of Brooklyn/Queens, loop through Manhattan, and then

To add on to DrJokepu, while trains depart frequently it can take quite a long time to get from the middle of Brooklyn/Queens, loop through Manhattan, and then go back out to the middle of the other, especially if it's a local train that stops at every station (versus express trains which only stop at select stations). As someone who had no idea how huge New York really is until I visited for my first time, Google Maps shows the center of Queens and center of Brooklyn being a 12.7 mile drive apart. If you have to loop through Manhattan that turns into a nearly 30 mile loop.