ΔE 15.3, loose: different enough that you should pick on purpose. Medium Sea Gray (RAF) is noticeably darker, more muted, warmer than Toxic Mist.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Medium Sea Gray (RAF) is noticeably darker, more muted, warmer than Toxic Mist.
The same difference applies the other way round: Toxic Mist is noticeably lighter, more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Toxic Mist on the colour wheel See Medium Sea Gray (RAF) on the colour wheel
All matches: Toxic Mist equivalents · Medium Sea Gray (RAF) equivalents