Every time a rider clocks up, they move faster than normal human beings. This means that they can age faster as well.
And since Hyper Clock Up can move faster than normal clock up, that also means that the rider will age faster as well.
Actually, the slowed down time is just an effect for style, the riders are merely moving incredibly fast, sub light speed even. Although this only creates more problems (why don't riders create deafening sonic booms every time they walk in clock up?) it means they are actually aging slower.
When a Worm mimics someone, it tries to kill whoever it's mimicking. All worms, both Salis and Native, are shown to do this. The only exceptions to this we've seen are the Mutant worm, which is seemingly one of a kind, and Hiyori, which mimicked somebody who was already dead. Tadokoro is a Worm...