Revealing mistake: The closing shot of the episode shows the lookout point platform where the suicide attempt happened...but also, below it, you can catch a glimpse of an additional platform, and a rope probably used for safety reasons as well. Needless to say, it was not featured in the dramatic shot of Holly looking down into the abyss. (00:46:55 - 00:47:40)
Continuity mistake: The chopper takes off from Higgie's un-birthday party, looking as usual. It flies over a shore to thwart Holly's plan, and doing so it has the flotation skids from a different chopper's stock footage. It is therefore also missing the birthday banner, that is present again in the finale. (00:45:10)
Audio problem: In their struggle on the lookout point, Don Cassidy throws the gun over the railing. A clattering noise is heard as if the gun fell on a solid pavement, but the way the action is shown, it went down in a spot where a few seconds later during the suicide attempt there's nothing but a freefall. (00:46:05)
Audio problem: The whole episode revolves around a radio DJ, who calls the various songs - however, for licensing issues, contrary to what the DJ advertises, the songs (including at least four Beatles hits, Elton John, and a version of Satisfaction that already appeared in the celebrated Season 3 opener) are not the originals, but stock covers.
Continuity mistake: Magnum is about to leave after the slightly awkward introduction to Holly Fox, but she calls him back saying "Maybe there *is* something you could help me with." He sticks his head back into the room, and you can see the glasses' left arm is above the shirt collar. Next shot and it went underneath. (00:13:40)