When waiting to board the plane at 1hr7min, Heather checks her phone seeing messages from her friends and the time on the phone is 14:13(2.13pm)...
What is supposed to be a few minutes later when she takes out her phone to ask Jack of his whereabouts, the phone's clock now says it is 12:40(12.40pm).. indicating instead of having waited for Jack to use the bathroom for a few minutes she has in fact gone back in time 1hr and 33mins.