Hi Rebecca
I am guessing I am right in assuming that at the end of the 4 days you DO NOT have a job?
If so, I would steer well clear of this as any airline you join will insist on you being trained in accordance with their standards.
Let's assume that T&T explain about safety features on a B737 - well, no 2 airlines B737's are ever the same, SEP equipment will be stored in different places and there could even be subtle differences with the type of equipment used (For example Draegar or L'Air Liquide smoke hoods).
I would steer clear of this and save myself some money and allow the airline that employs me to train me WITHOUT having some outside information that could potentially hinder my training with my new employer.