Thor in Strike Cannons mode

Question 1:

What happens to Thor when he starts his Strike Cannons mode against target (for example, colossus), but before he stuns the target will go out of Thor's range? Or, probably, Thor stuns it before entering into such mode?

Question 2:

Will Thor "stuns" enemy firing building (cannon, crawler, bunker) when using 'Strike Cannons" mode against them?

Thanks.

Question 1 - leaving the Thor's range

It depends on the stage of the ability. The strike cannon ability is actually composed of 3 stages - the preparation stage (switching to deployed mode), the barrage stage (shooting) and the resetting stage (returning to normal mode).

1. If a target leaves the Thor's range during the preparation stage, the Thor will pursue it (if it is able to) and then start the preparation mode again. In that case it behaves as if you just activated the ability beyond its range, and in a similar fashion to other targeted abilities.

2. If the target leaves the Thor's range during the barrage stage, the barrage will immediately stop (inflicting less than maximal damage) and the resetting stage will start. The only ways I know that a target can leave the Thor's range while both it and the Thor are still alive are if

   • the target is an Ultralisk (which are immune to stuns, so they can just walk away)
   • the target is being lifted by a Phoenix
   • the target is being sucked into a vortex
   • the Thor can no longer see the target (e.g. it's behind smoke and a unit providing vision has left, or the target became cloaked by a Mothership and the Thor's player does not have detection there)

Question 2 - Stunning buildings

Yes, the strike cannon "stuns" buildings as well, halting all production and research and disabling the attacks of defensive structures:

You can read more about this ability on this Liquidpedia entry.

The target is stunned as soon as the Thor finishes aiming and begins shooting, thus preventing the unit from leaving the Thor's range. If the target escapes the range of the Thor before he begins shooting he will attempt to move back into range. This can be particularly difficult when trying to focus Collossus as the protoss can easily pull his units back to prevent the cannon from occurring.

According to this post on team liquid all buildings are stunned when targeted. This includes cannons, planetary fortresses, and bunkers. The only exception I could find is the Ultralisk who is immune to stuns.