Copying my previous comment:
To put it in perspective. That Cobalt 60 source, when new in July of '63, emitted enough radiation to give you a 95% chance of death in 50 seconds. Drop and run indeed.
Today, after 60 years and about 11 half-lives, you would exceed the allowable annual dose limit for radiation workers in about 15 minutes. It would take you about a day (23.6 hr) to get that same 95% chance of death dose.
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