Simplify the following text for a Grade 5 native English-speaking person.
Original: The journey is almost at its end , Tristan drinks and Isolde takes half the potion for herself .
Simplified: Tristan agrees to drink the potion , now prepared by Brangaene , even though he knows it may kill him . As he drinks , Isolde snatches the rest of the potion from him and drinks it herself .