Depending upon the amount of ir192 it could be fatal in minutes.
Most industrial “xray” is actually performed with ir192 sources.
Over the years there have been accidents and occasional intentionally caused incidents with industrial strength sources.
If you search a person will find the after reports of these, going back into the 50s.
Anything that can create an image after traveling 6 to 10 feet and penatrating an inch or more of steel had the ability to damage biological objects.
Ok, I did some interweb searching, he gained access to Geotechnical density meters. Those are extremely low level sources used in measuring density of soil and asphalt.
The source is pretty well encapsulated, and so low of level the NRC doesn’t require much in the way of monitoring to use them. It would take a very long time of suitcase contact, to even be over one max. Level of exposure, and even longer before one has enough radiation to become sick.
Which explains how he gained access to them without anyone else being notified.