He can't. Charlie needed an excuse to stay in GK's space, so probably he made an offer to Jetstone (probably the same 250,000 schmuckers he had asked TV). But it's in his best interest that RCC doesn't win the battle. He can't be sure Parson and his artifact won't get damaged.
Unless Jetstone offers him a price comparable to the mathamancy artifact. We're talking about 500,000 schmuckers for one turn!
He jumps the wall, into the net they were carrying.