[Kiwami]

It's also an error-noise, although a different one. The Gunner can't read nor use the new body Shift Cars since they were made after Proto-Drive, and Chaser can only use Shift Cars that used this "old" technology. It would be cool though, if they ever release the black Type Speed that Proto-Drive used, that this one actually can be read and used with the Break Gunner.

But hey, maybe Proto-Drive will come back one day, maybe Chase get's his hand on his old Shift Car and he uses it after realizing who he is. It would be cool if they develop Chase's character to that end that he struggles with himself, but ultimately chooses his own path and becomes Proto-Drive once more to fight alongside Shinnosuke in the finale or something. I would dig it.