I would
1) make me some improvised palmwood waterskis
2) fabricate 30 feet of rope ("what d'you use for the rope: collected human hair from the back of my companion d'uh !")
3) attach the rope to myself and put the skis on
4) feed my chillin' companion's last stash of speed to the hungry sharks
5) throw a lasso (other end of the rope) at a passing shark and sail at lightspeed away from that island !
