A production source on the show assured RadioTimes.com that Mackie’s answer to the question was not a confirmation that her character would die.
“Pearl was answering about the scene where Bill appeared to die before being taken away for ‘treatment’ at the hospital, where viewers later discovered that she was eventually converted into a Mondasian Cyberman. This is not confirmation either way.”
In an interview with Graham Norton yesterday Mackie did her best not to give any clues, but she hinted that she would be keen to continue playing the character under new showrunner Chris Chibnall.
I mean, I’m instinctively distrustful of unnamed ‘sources’, but on the other hand the BBC and the Radio Times have a pretty close relationship, so who knows