Ovinomancer
No flips for you!
See my previous posts, I've already explained that immediately after the trigger might not mean what you claim here. The rules all refer to the "trigger", even though the trigger can be an action / movement / speaking / etc.. They can't use action instead of trigger, not because it represents how to resolve the readied action itself but because not all triggers are actions. So it's not proof of either interpretation being correct or incorrect.
There is not a single instance of the conflation of 'trigger' with 'action'. You're assuming things not in evidence to confuse the issue. The only way you'd be right is if the trigger stated is the same as an action. Actions can be triggers, but triggers do not have to be actions. If the trigger is part of an action, it doesn't stand that the reaction must wait for the action to complete when it's utterly unconcerned with whatever action created the trigger -- only the trigger matters.
It's you that arguing from a lack of evidence -- you're inventing words and reasoning not necessary to read the rules and then claiming that because the rules don't address your reasoning, they must therefore allow it. You have no evidence to support your choices, and, in fact, your choice rests entirely on attempting to read 'immediately' as somehow not immediate, but instead some time later, such that the reaction no longer makes any sense. You're insisting that the rule was written in a way such to require tortured reading of plain English AND that it be so randomly ineffective in it's stated intent that it becomes useless (waiting until the action is over will, quite often, invalidate the stated reaction to the trigger).
Seriously, your entire argument boils down to "well, immediately might not mean immediately the way we'd normally use it, but probably might mean sometime after, but not long after, you know, more of a 'shortly after' not, like, 'right after'." Are you seriously hanging your hat on that hook?