Why did Penguins Penalty Continue After Own Goal?

The Coyotes scored an unusual Power Play Goal wherein Penguins player Jansen Harkins remained in the box on a minor penalty even through Arizona scored a PPG. Pittsburgh had drawn a delayed penalty and attempted to kill off their penalty by pulling their goalie and playing keep-away in their defensive zone...accidentally scoring an own goal when Evgeni Malkin's pass to Kris Letang slid into the empty net.

Under the hockey rules, this is still considered a Power Play Goal, but one scored without a numerical advantage for Arizona. Instead of the usual 5-on-4 skater format of a power play, Pittsburgh had voluntarily pulled its goalie to create a 5-on-5 skater situation, effectively eliminating the numerical strength disparity for skaters in an attempt to waste time.

As a result, this qualifies as a goal scored during numeric equality, so even though Pittsburgh was serving a minor penalty, the penalty did not terminate upon the Coyotes goal, as there was no numeric advantage (for skaters) at the time of the goal.

Play thus resumed with Harkins remaining in the box for Pittsburgh and Arizona's Jason Zucker in the penalty box as well for the now-no-longer-delayed hooking minor penalty.

Video as follows:

Alternate Link: Penguins score own goal, but Arizona keeps its power play (on a minor)? Why?