Dr. MacGregor states at the Equator, where Devil's island is located, that the ground temperature is 150 degrees. The highest temperature ever recorded there is 106 degrees.
When Tony and Doug jump the guards who are manning the cannon, one guard punches Doug, who falls back on a large boulder. The boulder moves several inches when he hits it.
At the beginning a guard fires his rifle at escaping prisoners. We hear the sound of a gunshot but don't see evidence of his rifle being fired.
Despite the fact that in every previous episode they were switched to a new time within hours or days, upon arrival on Devils Island Doug and Tony immediately begin plotting escape. The odds of escaping are slim and the chance of being executed for the attempt are high. Yet they have absolutely no patience to wait for the time tunnel to rescue them.
Dr. MacGregor states that the ground temperature at the Equator is 150 degrees. Ground temperatures along the Equator during the month of March tend to be in the low to mid 70's.