ok I just want to chime in on the 'realism' aspect here.
using conventional ss13 math, 1 tile is equal to 2 meters
the radius of a flash bang blast affects 7 tiles out, which is 14 meters in one direction (which is a full 45 feet away to us americans)
assuming the blast is a perfect circle (its not because of tile mechanics) that gives the range of a flash bang 615.75 meters
now from wikipedia for the irl stats of the flashbang used by the US military today:
170–180 decibels and 6–8 million Candela within a 5-foot (1.5 m) radius
that would make the instant down radius to be less than 2 tiles, and light and sound dilutes very quickly as you move further away.
So in short, the blast radius and effects should probably be toned down, Its the future, so I'd say 3 tiles maximum effect and 5 tile terminus. Its still big enough to be useful but actually gives people time to move away rather than having it instantly end the conflict