Subaru BRZ 2018 Owner's Manual page 124

1-7. Safety information
Second impact
In an accident where the vehicle is struck from the side more than once, the
SRS side airbag and SRS curtain airbag deploy only once on the first
impact.
Example: In the case of a double side impact collision, first with one vehicle
and immediately followed by another from the same direction, once the SRS
side airbag and SRS curtain airbag are activated on the first impact, they will
not be activated on the second.
122
First impact
SRS curtain airbag
SRS side airbag