The betty model in the file isnt used, but it still exists. They just set a "fake model" in the same place as the original placed model is, not sure why
but i remember you could access teh grenade that you fired
like :
grenade detonate()
would make it explode, grenade delete(), would just remove it, but you have to do the waittill before it correctly ( I would show you what i mean but im on my work pc, not at home

), thats the only part youll need from the betty script