How did it happen could be a long story, which I think will be best left for two or so days from now. Only once we can positively id what it is, can we tell you the answer. It still may be nothing, although unlikely.
For a general answer, lack of sterilization or aseptic technique, inadequate verm layer, even slightly slowing the process though pint jars, contaminated syringes or spores, using whole rice, opening lids, etc are all possible factors.
As far as disinfecting the entire room, it is absolutely unnecessary. Disinfectants are for surfaces, mostly strictly. Lysol for instance will need to be sprayed over the surface so that it is completely wet and not just a light mist quickly. The disinfectant kills some microbes on contact, more after 5 minutes, and eventually reached that 99.9% value at about 15 minutes. However, most things we need to worry about in mycology, are gone by the midway point. Hardy viruses, for the most part, are what take the 15 minutes. But anyhow, that's just a bit of info for you moving forward.
Likely the possible contamination issue you have will not benefit from disinfecting. Trich and aspergillus are both spread in open air. You could Lysol all the live long day and they will still be there. Other contamination issues are inside the grains that may or may not have been properly sterilized. Either way, what is there (or isn't there), is there and there is very little you can actively do now. If it turns out to be these contaminations, I would instruct you to toss. It a great way to approach contams as a new grower instead of trying this and that while you spread spores around the whole house. If it is still iffy as to if this is a contam, I would probably say to try and birth. Only time will tell.