While in their submarine, the brothers end up in a Salmon run as they try to find the fish carrying the time thruster. As they travel with the Salmon, Salmon Shark who prey on the Salmon arrive, thinking the sub is a Salmon the Shark crushes the sub.
A minituarized Martin has been following Hero the Salmon on her Salmon run. They both swim into Aviva, who is standing in the river. Aviva and Martin follow Hero on part of her journey, when they get to one of Hero's obstacles, a waterfall.
This clip shows the different biosafety levels of a research facility. For each level, it lists the types of microorganisms that exist along with some of the viruses they could cause. It also shows the equipment and safety precautions used by the researchers at each level.