Do you see the quote above yours? That happened within about 2 weeks in a tank twice the size of yours...and with 20 of them, not 4.
YES, they can kill each other off easily and will...
If you HAVE to keep them in a 10g, pack it full of every tank decoration you have and as many fake plants as you can get in it. Make it so that they cant see each other no matter how hard they look. It will look junky but youll have to live with it if you want to do everything you can to make them last until you put them in a bigger tank...and even thats not a 100% guarantee they still wont do it. either that or go buy 3 10g dividers and separate them.
If you want to keep them alive, thats the only way to make sure they survive your ill fated decision to not have the proper size tank/environment and your decision to not have researched the fish, its aggression level, eventual size and personalities etc etc etc before you bought them.
Its no biggie, we all at some point and time do it or have done it...but have no doubt...they will kill each other...and fast!