Slicksters have temperature range of -30 to 70 degrees Celsius. The temperature in their environment rarely drops below 80 degrees Celsius. As a result, it's only a matter of time until they overheat and die, unless duplicants rescue them. They take a while to die because of their large mass, but they do die eventually.
Notable exception is slicksters that manage to "entomb" themselves in oil and stop moving. Those don't die until they start moving again.
Find slicksters and let them equalize their temperature with environment.