We did this exclusively at a great company I worked at for years. It was pretty great actually. Never felt stressed, we just collectively knocked out one thing after another in sequence.
I find there's a ton of value in "mob debugging"- if there's a serious issue, or your backlog or support queue is piling up with issues, turning the process into a live team exercise is fantastic.
Poor test coverage? Everyone sees the value in good tests in real time. Sloppy code that got through review? Everyone learns why you should be more diligent.
Tricky problem that needs an escape hatch from your framework to do something custom, or some advanced debugging tool usage to identify, or shed light on a database race condition? The impact of seeing it live is much better lasting than just getting a summary during a stand-up or a slack message.
I've not enjoyed pair programming, nor bottlenecking N programmers on 1 computer in general, but mob debugging on something gnarly in a shared cubicle - looking over each other's shoulders and getting a second set of eyes on something strange as they "WTF" out loud - has been repeatedly useful.
