Besides he has once promised Ethros that wherever he will go Ethros will go along with them. That they will witness the beauty of this world together, until one of them dies of old age or a non curative ailment.
And sorry but he ain't the one breaking this promise.
"Ermaan, she can't travel atop Ethros." Thomas tried to talk some sense to this guy.
" Ethros does not allow anyone to ride it except me, anyways. So, I don't see any problem." Ermaan counterback.
"But Ethros has the habit of running at the speed of light which the horses of your chariots haven't. If we have to dismiss your chariot and put Ethros in the equation then they won't be able to catch up with you and that would be a problem.
Not to mention at normal speed it takes two days and three nights worth of time. In the chariot, you can rest and even have your meals. It is more comfortable as an option than Ethros." Derek explained.