I thought I would jump in on this topic as I see a possible safety issue here.
LocTite is an amazing adhesive used in many industries. As David recently mentioned in a post under another topic it is used OFTEN in the toolmaking industry. In many cases in tool making we use it “in addition to” and not in place of a mechanical fit or bond. Examples would be locking a nut or screw in place, securing a light press fit dowel into a base plate or part etc. Where a strong bond is critical it’s best to have as much going for you as possible. In the case of a clock movement a great deal of potential power is sitting behind those barrel teeth which are meshing with that wheel pinion. That mainspring would be happy to release it’s full evil force in an instant if given the chance…sooo my personal feeling is that a good mechanical fit is necessary first, and the addition of loctite could also be helpful. These mechanical (riveted) connections do sometimes fail as your clock clearly demonstrates so adding some LocTite after properly securing the wheel to its arbor should help keep it from occurring a second time.
A sudden release of power can easily damage movement components and worse yet cause personal injury while winding or working with a movement when under power. As Paul mentioned properly securing the arbor would be the very first thing to do.
Hope this helps,