Engi's can still hide behind their sentry and repair it from damage while being shot by the loch-n-load though
The grenades rolling under the sentry are able to kill or damage and throw the engi however.
but imagine being a engineer and seeing a cluster of 4 grenades get pelted all at once into your sentry
Maybe the grenades would work the reverse of the loch n load
Like they only blow up after a set amount of time and don't explode on contact or something idk