Billy gave a flustered nod towards Tony, not sure he was processing right yet. He took a few breaths before starting to crawl towards Fury, when the shaking started up. He froze, eye squeezing shut, and he poured more power into the shield, wincing at the grinding noise.
Only once the train had been stopped by his barrier did he squint up at it, giving a sort of strangled noise and inching closer to Nick and Tony. This was bad.