Not to be confused with end to end related to Graffiti.
End-to-end / e-t-e is a time period in which you do one activity (work, study etc.) from the point of waking up to the point of going to sleep.
e-t-e periods are proven to be both difficult and dangerous regarding lack of sleep, physical activities etc.
The company is doing so bad that everybody needs to work e-t-e for a week straight...