I love how the rose is a recurring image in TPOTO for Phantom and Christine's love - in her dressing room, on the roof, at the graveyard... All these significant places to remind the audience that no matter who ends up with who, they are always a presence in each other's lives, even in death.
If you've seen or read the sequel LOVE NEVER DIES, it makes the final scene of TPOTO much more poignant.