Good news!
What about diff being so big that no new block shown in about 15-20 minutes? :-)
"blocks" : 2021151,
Qubit retargets every 20 blocks, by cutting difficulty up to half. It is possible to modify the algorithm, but it will require a hard fork. Even if we change difficulty with every block, there's not much you can do when 90% of the hash rate is suddenly removed, it is going to take time to find the next block before it adjusts, and then it will also take a few more blocks to adjust to target.