They might instead be a capable group caught up somehow in an incursion, or college students. Or alien college students with bad attitudes and unlicensed nuclear weapons.
Generally, a group might cross to another tangent unexpectedly (and might or might not be the only ones in the vicinity who do so, rather than just being vaporised) if they have some reason to be close to, but not in, a location where experimental or otherwise unstable dimension-bending technology is in use.
If the passage between tangents is a doorway or roadway sufficiently ordinary-looking that characters might plausibly not notice it, they might simply walk or drive through. In fact, many people say this has happened to them for varying periods.