I'm poking at a bug I found - in V2, tried repeating the same in v1.1 with no success. did not try in the original but vaguely recall this may have been possible.
It appears that reading certain signs, then lockpicking doors is screwing with the combat scripts, does not seem to be quite reliable
The most consistent way I can reproduce this, at least in V2 (and also, at least on my machine only):
Take the out-of-the-box starter party, go immediately into the Catacombs in the palace. read the "Gates of Kawahara" sign. Lockpick with the shukenja/monk (to be clear here, the Senshi is still party lead so I am spamming p-2-m), there will be a bunch of Kaibu in the door behind. The kaibu should spam a party death attack instead of their usual melee.
there is some inconsistency with it as I have been able to sometimes trigger it in Kawa by reading the Mist Dragon Inn sign, then lockpicking into the kichigai fight on the west half, and have seen it with random Ogres once or twice... There's some sensitivity to the party member position (can sometimes trigger if the lockpicker is person 1, but not party lead)
I'm guessing the party-kill spell script is a filler/fallback combat action, intended for when an enemy's regular combat script does not load properly. Which would mean something in the read, lockpick command order is messing with some incorrect memory addresses?