AUS - Good morning.
Here is my input on your horrible carnage scenario.
I am sceptical and here is why :
Accomodation ladder
Ship gangways, used for safe embarkation and disembarkation, must be properly secured, maintained, and operated according to specific guidelines.
The safe working load should be clearly marked, and the gangway should only be rigged by authorized personnel.
SOLAS Regulations:
Gangways and accommodation ladders are subject to SOLAS regulations, including requirements for testing and examination.
LEGISLATION: Accommodation ladders and gangways fitted on ships constructed before or replaced after 1 January 2010, should, to the extent possible, adhere with the IMO circular MSC.1/Circ.1331 – IMO “Guidelines for Construction, Installation, Maintenance and Inspection of means of Embarkation and Disembarkation¹”. This circular should be referred to in conjunction with the Safety of Life at Sea (SOLAS) regulation II-1/3-9 (Means of Embarkation on and Disembarkation from Ships).
Design and Construction: Gangways must meet design standards, including those specified in ISO-7061 or equivalent, and have adequate fencing. They should also be electrically insulated to prevent electrical continuity between the ship and shore.
Angle of Inclination: The angle of inclination should not exceed the designed limits (generally 30° from horizontal), unless designed for greater angles.
Safe Working Load: The gangway’s safe working load must be clearly marked, and the maximum capacity should never be exceeded.
Maintenance: Gangways require regular inspection and maintenance, including checks for wear, damage, and proper functioning of safety systems.
Training and Authorization: Only authorized personnel, trained in gangway operations, should rig and operate the gangway.
Safety Nets: In some cases, safety nets are required underneath the gangway.
Risk Assessment: A risk assessment should be completed before rigging the gangway.
There is also ship’s register of all lifting devices and wires on board frequently checked by - you name it -everyeffingbody . And all entries there must be accurate , ship shape and reflecting the current condition . I would skip SMS instructions ,procedures and all the blah blah blah .
Also for as long as I have been using computerised PMS ( planned maintenace system ) (28 years) , the works on the gangway system have been featured there prominently .
See also : https://britanniapandi.com/wp-content/uploads/2024/09/Britannia-Loss-Prevention-Guidance-Gangways-A-Practical-Guide.pdf
So this thing is really important and as Master per SMS instructions i had to sign all sorts of gangway use permits & R.A.s . Well i must confess i always signed it inblanco . 
Now let me address your worries and your nightmarish vision of carnage from the point of elementary phisics.
For this purpose I made an awkward drawing in paintbrush having no better graphics application . But i think it will do , showing that your terrible scenario is highly unlikely . But may be some viewer here will come with some rebuttal then i would be only happy to read it .
Cheers