Data World - S4-E17
Continuity mistake: When Mr. Chandler is on the roof with Quinn and says they should talk in his office, he's standing on Quinn's right side. In the next shot, Mr. Chandler is on Quinn's left side.
Continuity mistake: Near the end of the episode, when Maggie goes into the Suspended Animation chamber, she shoots the Pressure Control box & destroys it. The Temperature Control box is not hit. Moments later, the Temperature Control box is the one that's destroyed.
Revelations - S4-E22
Revealing mistake: When the group is fleeing from the cops, there's a shot of the road as they're turning. The camera used has a crack, or piece of debris, on it at the top to the left. The black line doesn't move as the camera pans across the road.
Continuity mistake: When Diana is at the cafe with her double, the book on the table changes position between shots. Some shots the binding is perpendicular to her body and in other shots it's more parallel with it.
The Return of Maggie Beckett - S5-E9
Other mistake: The group slides to Fresno, where there is a monument to Maggie Beckett and the astronauts that were lost on an Intrepid mission to Mars. On the memorial stone, her name is misspelled as Maggie Becket, not Beckett as everywhere else.
Chosen answer: Remember at first Quinn's timer is working perfectly (it's only because they slide off the ice age world early that it begins to malfunction) & given Quinn's intellect he would have devised a way that he could open a wormhole near him so he wouldn't be trapped on that world for 29 years.