This is Terror Tales for March-April 1937, cover by John Drew. The ISFDB entry for this issue is here. I found this version of the cover on this Pinterest page. The version preserved by Galactic Central is a bit smaller but also a bit sharper:
![version preserved by Galactic Central](http://www.philsp.com/data/images/t/terror_tales_193703-04.jpg"){kind=link}
Pulp Parade #28: Zap!
They’re not mad scientists, they just had the bad luck to be working at a medical center equipped with a Therac 25.
http://courses.cs.vt.edu/professionalism/Therac_25/Therac_1.html