The thing about Tsaheylu was that it went both ways. Just as Jake could tell Banshee how to fly and where he'd like to go, Banshee could direct his Na'vi to the nearest water so they could go swimming or get him to scratch a particularly bothersome itch, among other things. They could also share thoughts and pick up on things that the other noticed. Case in point, Banshee heard what Aaron said.
Banshee was a proud ikran who flew very well. He hissed his displeasure, and Jake's eyes widened as he realized what was about to happen. "Shit. Hold on!" he shouted back at Aaron, and then tightened his grip on him as Banshee proceeded to put on a particularly challenging show of aerobatics. Jake remembered some of the terms from before, either back when he was a Marine or when he was talking with Trudy about flying; Immelmann, Cuban eights, inside and outside loops, barrel rolls and others he just didn't have a name for. He fought for control the whole time, but Banshee was just as stubborn and determined as he was, and it wasn't until they were reaching the top of a really fucking steep climb that Jake managed to get anywhere. "What the fuck?" he yelled at the ikran, "Castle! Now!"
So Banshee fell into an equally steep dive towards the castle's courtyard.