"HELP ME!" screamed Jacob, now clutching onto the bridge for dear life.
"Jacob!" Newt gasped as he ran forward heroically to save his loyal friend. He bumped into Nagini a little as he dived for Jacob, but he still didn't notice she was there.
"Help me, I don't know how to swim!" yelled Jacob, as though knowing how to swim would even make a difference after a fall from that height.
"Don't worry, Jacob, I've got you!" said Newt, grasping Jacob's hand rather than using magic because then the plot wouldn't work. But it wasn't enough! Jacob was falling and taking Newt with him!
"Newt - I mean, Mr. Scamander!" yelled Tina, accidentally revealing her true, very first-name-basis feelings for Newt. By the way, it turns out Tina favors a mixed-economy welfare-state system and so should you. This is canon now.
Anyway, Newt and Jacob fell in the river.
"Great, now I'm alone in this jungle all by myself," said Tina, still not noticing that Nagini was there.