You are correct, 3 elders cannot control a session. The session at Midway was comprised of 12 (11 ruling elders and 1 teaching) of which 4 ruling elders (1/3 of the session) have been charged and removed from office. Additionally, there have been multiple complaints filed against the actions of the session in which it has been found that the session violated the BCO. See the examples below. SolaScriptura should be familiar with SJC case 2019-03 as he was a member of the Northwest GA Presbytery at the time.
Your own blog description says you have no connection with the PCA, nor the church in question. And your blog is stuff that most of us have no business knowing about. Leave all this to the officers Christ has appointed; otherwise you are rushing to mischief and sowing discord. And do not cause the rest of us to think badly about persons concerning whom we do not--and cannot--have all the facts. Beware prying into matters you are not close to. You may be in addition be guilty as a "false witness".
These six things doth the Lord hate: yea, seven are an abomination unto him:
A proud look, a lying tongue, and hands that shed innocent blood,
An heart that deviseth wicked imaginations, feet that be swift in running to mischief,
A false witness that speaketh lies, and he that soweth discord among brethren.