🏰anging Towers of Babylon🏰

I have a question 4 @Master_Mind09:
"What if black plays Re7 instead of Bxa7 on 2. move?"
Obviously the threat of mate is looming large (Qg7#) & white must have a mating line, which is not evident for me. So what is your answer?
Much obliged!
& as'n days of old so was Foretold: White's 'n total control, the shots 2 call, black 2 fall in 2+null, so start this ball with...