I'd call you on that narration (cue the table argument!): the hesitation occurs before I take a stab, not during; and barring outside intervention once the moment of hesitation passes I should be back to status quo with nothing else having changed. From there, knowing I'd hesitated once, it'd be on me-as-player to decide whether to go through with it anyway or not.
--- the target disarmed me. Did he, really, or could I (try to) fend off the attempt? UNRESOLVED
--- if the disarm succeeds, you declare by fiat I can't get my weapon back in time to do anything e.g. throw it at his fleeing back.
--- if the disarm fails, are we now in combat? Do I get to (try to) stab at him again only this time with him fully able to defend? Does he get to (try to) clock me one and leave me sprawled on the ground? UNRESOLVED
--- the target flees. Am I able to react in time to tackle him or get in his way? UNRESOLVED
--- the target is gone. If I can't stop him, am I able to see which way he goes? Also, if I inflicted any wounds are they slowing him down and-or is he leaving a trail of blood for me to follow? UNRESOLVED
Where's the detail here?
Resetting to status quo completely violates the rules for BW. If the intent is "I murder the innkeeper" (that bastard!) with a task of "stabbing him" (take that!), returning to the same scene four seconds later with no change in circumstance is a misplay. Things must be complicated by the failure. The good news is (for some sets of good news, I suppose), BW encourages discussion of stakes up front. So you should be hearing what's going to happen on failure, at least roughly, before the roll.
This does, though, point to something else I dislike about some of these systems: you just squashed about six different detailed actions into one brief mostly-fiat narration without giving any opportunity for reaction or granular resolution:
--- I took a stab at my target. Did I wound him? Kill him anyway? Miss completely? UNRESOLVED
RAW, you did not take a stab at him, you hesitated and missed your window.
--- the target disarmed me. Did he, really, or could I (try to) fend off the attempt? UNRESOLVED
This could happen next. Depending on the character and their traits, I might be inclined to make it a Vs Test at penalty or have the situation pick up in a desperate struggle for the knife.
--- if the disarm succeeds, you declare by fiat I can't get my weapon back in time to do anything e.g. throw it at his fleeing back.
If he could disarm you, such that I ellided the roll, I'd let you go after him to get the weapon back.
--- if the disarm fails, are we now in combat? Do I get to (try to) stab at him again only this time with him fully able to defend? Does he get to (try to) clock me one and leave me sprawled on the ground? UNRESOLVED
We could absolutely come around to him reaching for the club under the bar and go to Fight!
--- the target flees. Am I able to react in time to tackle him or get in his way? UNRESOLVED
Maybe not, but it's just four seconds -- you could chase him out the door and then we'd have a foot chase.
--- the target is gone. If I can't stop him, am I able to see which way he goes? Also, if I inflicted any wounds are they slowing him down and-or is he leaving a trail of blood for me to follow? UNRESOLVED
It's four seconds, how far can an innkeeper run? Assuming he's not a professional athlete and can't run in a straight line (because of circumstances, not some sort of other issue), it'd be well less than 40 yards.
Yes, it's all unresolved, but that's what we're playing for. We're playing to find out what happens! (In this situation, at least. I thank you for your cooperation!)