I asked Chat GPT:
Approximate unshielded dose rates:
At 1 m: ≈ 5.2×10^4 Sv/h (≈51,800 Sv/h) — fatal essentially instantaneously (seconds or less).
At 3 m: ≈ 5.8×10^3 Sv/h — fatal within seconds.
At 10 m: ≈ 5.18×10^2 Sv/h — fatal within tens of seconds.
At 30 m: ≈ 5.8×10^1 Sv/h — severe, life‑threatening in minutes.
At 100 m: ≈ 5.2 Sv/h — dangerous; a few hours would produce fatal/serious acute radiation syndrome.
(For perspective: an acute whole‑body dose of ~4–5 Sv often causes death without intensive medical care; 1 Sv already causes significant radiation sickness.)
These are conservative, point‑source, unshielded estimates for whole‑body dose from the gammas. Being closer, or in contact, or staying in the field increases dose proportionally.
Back to me again. I'm sorry my radioactive physics game is weak and I had to speculatively look it up. That's a lot of downvotes, yet no one decided to share the math themselves.