Me, joking: "for that you'd need a Geiger counter and a fire alarm"
"There's probably a Geiger counter in @lcamtuf's old stuff"
And sure enough:
@lcamtuf the party has since moved to finding batteries for that thing, but I had "work" to do.
The smallest tick on the scale seems to correspond to 100uSv/h (also the units are weird, this should be scaled in something like kerma in air and not does, but I assume this is scaled in dose that water/tissue would absorb), so clearly unhealthy environment to stay in, but you might be able to see some intermittent not-too-unhealthy sources with that (e.g. xray machines have exposure times below a second and give total does of a fraction of uSv, so that gives dose rate of fractions of mSv/h).