GEOMETRIC SPECULATION. “If two particles moving in a straight line directed opposite to each other in the spacetime then they can collide at any point. Collision of the particles occurs close to the outer horizon of the white hole. The second particle emanates from the white hole region should lapse near the bifurcation point but not crosses this point, because if it crosses this point, it would come into the T−region instead of R−region.”
https://link.springer.com/chapter/10.1007/978-3-030-51081-7_62