Our fire dept. and college security have policy that no one returns into
building until fire alarm is silenced AND "All Clear" is given by fire dept.
Incident Commander. Security officers are responsible to secure the building
(from outside). "Fire line" barrier tape is used if necessary.

Any infraction of this policy could be considered a minor misdemeanor
(failure to assist the FD), a fourth degree misdemeanor (misconduct at
emergency), or a second degree misdemeanor (obstruction of pubic official).

Actually, the college has a very good "educational" system to disburse
information about appropriate actions during such emergencies (and a good
disciplinary system to back it up!).