Summary: The Doctor has been outnumbered before, but rarely this badly.
How many Daleks were out there? Thousands? Millions? Billions? He’d been vastly outnumbered many times before, had defeated the Daleks more times than he could easily remember, but this time the odds seemed insurmountable. That was why he’d sent Rose to safety. He couldn’t risk her life along with everybody else’s.
He had a plan, but there wasn’t enough time to make the necessary adjustments to the Delta Wave. If he used it, the Daleks would die, but so would every human in the wave’s path. If he didn’t use it, they were doomed anyway.