Light a flare ane throw it in between the Spinosaurus and the T-rex. Lure the raptors over to the Ankylosaurus and hope it distracts them, once the Ankylosaurus or the Raptors die, I will use a spear I carved from a fallen tree branch to gouge out the Ankylosaurus' eyes or stab oncoming Raptors. By this time the Spinosaurus and the T-rex are probably done fighting, (hate to break it to you, but the T-rex most likely won) I'd take off running and hope to escape whoever is chasing me. That's how I'd do it.