Dewdrop – Welcome!
The nature of your queries create an impression that you may still not be fully versed on firearm laws in effect here in Canada - in which case it is imperative that you go over the regulations again with diligence and understand the roles/responsibilities associated with firearms ownership at both Federal as well as Provincial levels.
I must reiterate that firearms regulations pertinent to storage and transportation DO NOT permit the type of practice that you have mentioned. There are, however, a few exceptions only where the regulations address the need to maintain a loaded non-restricted firearm (with no round in the chamber other than a muzzle loading rifle) and that too ONLY in specific cases relevant to hunting scenarios and/or in order to dispose of certain wild life classified as pests. In other words, the concept of home defense here in Canada does not exist (by law) in any shape or manner although one may envisage different theories.
On the other hand, the fact may be that your questions do not at all pertain to ownership of firearms in Canada – I suspect the later may well be the case.
Consequently, from a perspective of HD requirement(s), any discussion here on the features or rather the cons regarding the Baikal MP-153 may not address your personal scenario.
Having said that, personally, I would like to think that if an individual was limited to a firearm such the MP-153 and was also faced with an element of threat to his/her life/property etc where that firearm may become the first line of defense in a potentially dangerous situation – then common sense should dictate that the individual must also be always prepared to respond to such threats by keeping at hand that MP-153 shotgun already locked and loaded and not have to “spoon feed by it’s wide open mouth” as you put it. If you already own the shotgun, then it would best be simpler to accept the fact that the MP-153 isn’t designed the way you would like to see that work. Alternately, get another firearm that would fully conform to your individual requirements and offer peace of mind.
A rather more important question that would come to surface is how prepared/trained (in both mind and body) that individual may be in order to act calmly and effectively under pressure when confronted with such a situation!