Board Thread:Questions and Answers/@comment-5872914-20160605102737/@comment-1173941-20160611012531

If you die in Underworld, the Avatar can't be used again, unless you re-activate it to a living state.

If Gabriel was to die, he wouldn't be able to use the Vector account anymore, because the Ocean Turtle is on lock down, and they can't access the main control room to re-activate the account. So he would need to log in with a different account.