Neither Halon 1301 nor FM-200 are particularly safe for longer term exposure. They are not innocuous and long-term exposure is not recommended. If you are in a room where the gas fire suppression system discharges, leave immediately.
At high concentrations (which may happen in some parts of a space where it is discharged, in order to ensure extinguishing concentration in the whole space) both are an asphyxiant.
Halon 1301 "In low concentrations may cause narcotic effects. Symptoms may include dizziness, headache, nausea and loss of co-ordination."
"However, inhaling high concentrations of FM-200® vapor may cause temporary nervous system depression with anesthetic effects such as dizziness, headache, confu- sion, loss of coordination, and even loss of consciousness.... If vapors are inhaled at a concentration of 105,000 ppm and higher, the heart may become sensitized to adrenaline, leading to cardiac irregularities and, possibly, cardiac arrest. Similar effects are observed with many hydrocarbons and halocarbons at high concentrations. The likelihood of these cardiac problems increases if the person is under physical or emotional stress." I think I'd be under some emotional stress if I was being gassed in an aircraft hold.
Sources:
https://www.boconline.co.uk/internet...4634.pdf?v=1.0
https://www.chemours.com/FE/en_US/as...M-200_PUSH.pdf