Juvenile T-rex

your time machine broke and you ended up on the end of the Cretaceous Period, so you have to survive. Your equipment: a blaster (It can be recharged with sun light) a medical kit your broken time machine a few protein bars and last but not least a water bottle that can filter river water. you see a juvenile T-rex being cornered by an adult T-rex (if you save him he will be loyal to you by the rest of his or your live).