[AmericanInTokyo]

My guess is one of three:

a) hidden ampules of cyanide bitten off (such as hidden in the cotton or charcoal filter of a cigarette;

b) tried to bite tongues off.

c) tried to break away somehow and throw themselves off a steep ledge.

The hand grenade thing would not work if they were in custody.

All according to special North Korean force textbooks. Has all the markings of a Kim Jong il planned attack and I would not doubt if "sonny boy" (with Fish Lips as royal chamberlain and mentor for the kid) was also given a planning role, so if successful, they could internally use it to promote his take over of the ship of state as a last resort, solidifying his hand with the Party, State and Army.

[TigerLikesRooster]

This thing is not over. There is more to come. The next is probably a nuclear test. It is likely that they would pull it off this time around, leaving no doubt to outsiders.
That would be also credited to Chia junior.