You shouldn't let yourself get to that point. Your alerting system should alert you when disk is at 70% or something with a ton of margin. If it's not set up that way, go stop what you're doing and fix that. (Seriously.) If you're running your systems so they usually run at 90% disk usage, go give them more disk (or rotate logs sooner).
And even assuming all that fails and I'm in that situation where I have seconds until the disk hits 100%, I would much rather the service crashes than make a mistake and delete something critical.
If someone is breathing over your shoulder, you can even enlist them to co-pilot what you're doing. Even if they're not technical enough to understand, talking at them what you're about to do will help you spot mistakes.