Short answer- no. Long answer below.
Technically, sentry does not record anything. Dashcam does.
What you see on live cam IS being recorded- but it will be overwritten in time.
The way the system works is this:
If the car is on/awake, and dashcam is on, then dashcam is always recording to the recent folder on the USB stick. Always.
That's the ONLY place video is ever recorded to.
Any footage older than 1 hour is overwritten by default.
There's 2 other folders on the stick- saved, and sentry. How video gets in there is either:
If you manually save dashcam footage (either pressing the dashcam button or honking if you have that enabled) it will move existing video (last 10 minutes worth) to the saved folder. Nothing "new" gets recorded. (it also does this in an accident, I think if airbags deploy specifically). Content in the saved folder is NEVER overwritten.
or
If sentry mode (which DOES NOT RECORD VIDEO) goes to an alert state, then it will move existing video (last 10 minutes worth) to the sentry folder. Content in the sentry folder is NEVER overwritten UNLESS your drive is nearly full- then it will be. (I think this happens at 90 or 95% full?)
So anyway, that's how the system operates, and what records and where.
If you pull up live view right now, watch it for a couple of minutes-- -then walk out to your car and remove the USB drive-- that couple of minutes you saw live will be recorded in the recent area of the drive.
But there's no way to MANUALLY trigger that video being moved to the sentry folder ever- that only happens when sentry itself gets sent to an alert state. There are ways to manually trigger video being moved to saved, but only when you're IN the car.