So, what your saying is the shard locked the object in place relative to the planet Clock is on?See, that can't possibly be true. If it was, then anything he used his power on would be locked in one position in space as the planet moved away from it at incredible speeds. Shards also can't manipulate time, any time manipulation they appear to do so is pure trickery using dimensional shenanigans. Since Clockblocker isn't causing people and objects to go spinning off into space every time he uses his power, it can't be a complete freeze of all movement. Hell, if he was completely freezing all movement like that, he'd be killing anyone he used that power on for longer then a few seconds because they would be unable to breath and their blood would be unable to flow.
As far as I can tell, when a person becomes locked, they literally stop EVERYTHING including thought, otherwise they'd remain aware of their surroundings and people talking near them. From every instance we've seen of a person being locked is "Oooo, stuff moved while I was 'locked'".
Why didn't power testing show that an object could be superheated while locked? You'd think that would be something he was aware of, and had probably done at least a couple times while "playing" with his powers. I can't believe Armsmaster wouldn't try to burning a piece of paper while it's locked, just to see what happens to it. As soon as it goes critical when the lock stops, you immediately know that's a really, really bad idea to try again unless you're prepared for a really high energy event.