Wsoukkachang Had a look - and bugs like this going to take awhile to figure out.
1) You need to comment - hard to understand you thought process, and what connects what without comments, and next month you would have forgotten it too, so comments help others see what you doing, but also remind you what you did - lol.
Seriously, it is going to take considerable amount of time to make sense of uncommented events even before trying to track down the underlying issue.
2) I just tried it and made players(2 and 4 win) and no issue with card not being destroyed.
I would suggest making use of break points (rightclick on event and toggle break points) you can then move through the code in debugger mode from breakpoint to breakpoint to narrow down the issue.
Sidenote: nice job with multiplayer plugin nice job with game, still a long way to go, but very nice.
NEED TO COMMENT THOUGH! lol - Yes I'm shouting